# pyparsing module

## pyparsing module - Classes and methods to define and execute parsing grammars

The pyparsing module is an alternative approach to creating and executing simple grammars, vs. the traditional lex/yacc approach, or the use of regular expressions. With pyparsing, you don’t need to learn a new syntax for defining grammars or matching expressions - the parsing module provides a library of classes that you use to construct the grammar directly in Python.

Here is a program to parse “Hello, World!” (or any greeting of the form `"<salutation>, <addressee>!"`), built up using `Word`, `Literal`, and `And` elements (the `'+'` operators create `And` expressions, and the strings are auto-converted to `Literal` expressions):

    from pyparsing import Word, alphas

    # define grammar of a greeting
    greet = Word(alphas) + "," + Word(alphas) + "!"

    hello = "Hello, World!"
    print (hello, "->", greet.parseString(hello))

The program outputs the following:

    Hello, World! -> ['Hello', ',', 'World', '!']

The Python representation of the grammar is quite readable, owing to the self-explanatory class names, and the use of ‘+’, ‘|’ and ‘^’ operators.

The `ParseResults` object returned from `ParserElement.parseString` can be accessed as a nested list, a dictionary, or an object with named attributes.

The pyparsing module handles some of the problems that are typically vexing when writing text parsers:

> - extra or missing whitespace (the above program will also handle “Hello,World!”, “Hello , World !”, etc.)

> - quoted strings

> - embedded comments

### Getting Started -

Visit the classes `ParserElement` and `ParseResults` to see the base classes that most other pyparsing classes inherit from. Use the docstrings for examples of how to:

> - construct literal match expressions from `Literal` and `CaselessLiteral` classes

> - construct character word-group expressions using the `Word` class

> - see how to create repetitive expressions using `ZeroOrMore` and `OneOrMore` classes

> - use `'+'`, `'|'`, `'^'`, and `'&'` operators to combine simple expressions into more complex ones

> - associate names with your parsed results using `ParserElement.setResultsName`

> - access the parsed data, which is returned as a `ParseResults` object

> - find some helpful expression short-cuts like `delimitedList` and `oneOf`

> - find more useful common expressions in the `pyparsing_common` namespace class

class pyparsing.And(exprs, savelist=True)

  Bases: `pyparsing.ParseExpression`

  Requires all given `ParseExpression` s to be found in the given order. Expressions may be separated by whitespace. May be constructed using the `'+'` operator. May also be constructed using the `'-'` operator, which will suppress backtracking.

  Example:

      integer = Word(nums)
      name_expr = OneOrMore(Word(alphas))

      expr = And([integer("id"), name_expr("name"), integer("age")])
      # more easily written as:
      expr = integer("id") + name_expr("name") + integer("age")

  checkRecursion(parseElementList)
  parseImpl(instring, loc, doActions=True)
  streamline()

class pyparsing.CaselessKeyword(matchString, identChars=None)

  Bases: `pyparsing.Keyword`

  Caseless version of `Keyword`.

  Example:

      OneOrMore(CaselessKeyword("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD']

  (Contrast with example for `CaselessLiteral`.)

class pyparsing.CaselessLiteral(matchString)

  Bases: `pyparsing.Literal`

  Token to match a specified string, ignoring case of letters. Note: the matched results will always be in the case of the given match string, NOT the case of the input text.

  Example:

      OneOrMore(CaselessLiteral("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD', 'CMD']

  (Contrast with example for `CaselessKeyword`.)

  parseImpl(instring, loc, doActions=True)

class pyparsing.Char(charset, asKeyword=False, excludeChars=None)

  Bases: `pyparsing._WordRegex`

  A short-cut class for defining `Word(characters, exact=1)`, when defining a match of any single character in a string of characters.

class pyparsing.CharsNotIn(notChars, min=1, max=0, exact=0)

  Bases: `pyparsing.Token`

  Token for matching words composed of characters not in a given set (will include whitespace in matched characters if not listed in the provided exclusion set - see example). Defined with string containing all disallowed characters, and an optional minimum, maximum, and/or exact length. The default value for `min` is 1 (a minimum value < 1 is not valid); the default values for `max` and `exact` are 0, meaning no maximum or exact length restriction.

  Example:

      # define a comma-separated-value as anything that is not a ','
      csv_value = CharsNotIn(',')
      print(delimitedList(csv_value).parseString("dkls,lsdkjf,s12 34,@!#,213"))

  prints:

      ['dkls', 'lsdkjf', 's12 34', '@!#', '213']

  parseImpl(instring, loc, doActions=True)

class pyparsing.CloseMatch(match_string, maxMismatches=1)

  Bases: `pyparsing.Token`

  A variation on `Literal` which matches “close” matches, that is, strings with at most ‘n’ mismatching characters. `CloseMatch` takes parameters:

  > - `match_string` - string to be matched

  > - `maxMismatches` - (`default=1`) maximum number of mismatches allowed to count as a match

  The results from a successful parse will contain the matched text from the input string and the following named results:

  > - `mismatches` - a list of the positions within the match_string where mismatches were found

  > - `original` - the original match_string used to compare against the input string

  If `mismatches` is an empty list, then the match was an exact match.

  Example:

      patt = CloseMatch("ATCATCGAATGGA")
      patt.parseString("ATCATCGAAXGGA") # -> (['ATCATCGAAXGGA'], {'mismatches': [[9]], 'original': ['ATCATCGAATGGA']})
      patt.parseString("ATCAXCGAAXGGA") # -> Exception: Expected 'ATCATCGAATGGA' (with up to 1 mismatches) (at char 0), (line:1, col:1)

      # exact match
      patt.parseString("ATCATCGAATGGA") # -> (['ATCATCGAATGGA'], {'mismatches': [[]], 'original': ['ATCATCGAATGGA']})

      # close match allowing up to 2 mismatches
      patt = CloseMatch("ATCATCGAATGGA", maxMismatches=2)
      patt.parseString("ATCAXCGAAXGGA") # -> (['ATCAXCGAAXGGA'], {'mismatches': [[4, 9]], 'original': ['ATCATCGAATGGA']})

  parseImpl(instring, loc, doActions=True)

class pyparsing.Combine(expr, joinString='', adjacent=True)

  Bases: `pyparsing.TokenConverter`

  Converter to concatenate all matching tokens to a single string. By default, the matching patterns must also be contiguous in the input string; this can be disabled by specifying `'adjacent=False'` in the constructor.

  Example:

      real = Word(nums) + '.' + Word(nums)
      print(real.parseString('3.1416')) # -> ['3', '.', '1416']
      # will also erroneously match the following
      print(real.parseString('3. 1416')) # -> ['3', '.', '1416']

      real = Combine(Word(nums) + '.' + Word(nums))
      print(real.parseString('3.1416')) # -> ['3.1416']
      # no match when there are internal spaces
      print(real.parseString('3. 1416')) # -> Exception: Expected W:(0123...)

  ignore(other)

    Define expression to be ignored (e.g., comments) while doing pattern matching; may be called repeatedly, to define multiple comment or other ignorable patterns.

    Example:

        patt = OneOrMore(Word(alphas))
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj']

        patt.ignore(cStyleComment)
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd']

  postParse(instring, loc, tokenlist)

class pyparsing.Dict(expr)

  Bases: `pyparsing.TokenConverter`

  Converter to return a repetitive expression as a list, but also as a dictionary. Each element can also be referenced using the first token in the expression as its key. Useful for tabular report scraping when the first column can be used as a item key.

  Example:

      data_word = Word(alphas)
      label = data_word + FollowedBy(':')
      attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join))

      text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
      attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))

      # print attributes as plain groups
      print(OneOrMore(attr_expr).parseString(text).dump())

      # instead of OneOrMore(expr), parse using Dict(OneOrMore(Group(expr))) - Dict will auto-assign names
      result = Dict(OneOrMore(Group(attr_expr))).parseString(text)
      print(result.dump())

      # access named fields as dict entries, or output as dict
      print(result['shape'])
      print(result.asDict())

  prints:

      ['shape', 'SQUARE', 'posn', 'upper left', 'color', 'light blue', 'texture', 'burlap']
      [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
      - color: light blue
      - posn: upper left
      - shape: SQUARE
      - texture: burlap
      SQUARE
      {'color': 'light blue', 'posn': 'upper left', 'texture': 'burlap', 'shape': 'SQUARE'}

  See more examples at `ParseResults` of accessing fields by results name.

  postParse(instring, loc, tokenlist)

class pyparsing.Each(exprs, savelist=True)

  Bases: `pyparsing.ParseExpression`

  Requires all given `ParseExpression` s to be found, but in any order. Expressions may be separated by whitespace.

  May be constructed using the `'&'` operator.

  Example:

      color = oneOf("RED ORANGE YELLOW GREEN BLUE PURPLE BLACK WHITE BROWN")
      shape_type = oneOf("SQUARE CIRCLE TRIANGLE STAR HEXAGON OCTAGON")
      integer = Word(nums)
      shape_attr = "shape:" + shape_type("shape")
      posn_attr = "posn:" + Group(integer("x") + ',' + integer("y"))("posn")
      color_attr = "color:" + color("color")
      size_attr = "size:" + integer("size")

      # use Each (using operator '&') to accept attributes in any order
      # (shape and posn are required, color and size are optional)
      shape_spec = shape_attr & posn_attr & Optional(color_attr) & Optional(size_attr)

      shape_spec.runTests('''
          shape: SQUARE color: BLACK posn: 100, 120
          shape: CIRCLE size: 50 color: BLUE posn: 50,80
          color:GREEN size:20 shape:TRIANGLE posn:20,40
          '''
          )

  prints:

      shape: SQUARE color: BLACK posn: 100, 120
      ['shape:', 'SQUARE', 'color:', 'BLACK', 'posn:', ['100', ',', '120']]
      - color: BLACK
      - posn: ['100', ',', '120']
        - x: 100
        - y: 120
      - shape: SQUARE

      shape: CIRCLE size: 50 color: BLUE posn: 50,80
      ['shape:', 'CIRCLE', 'size:', '50', 'color:', 'BLUE', 'posn:', ['50', ',', '80']]
      - color: BLUE
      - posn: ['50', ',', '80']
        - x: 50
        - y: 80
      - shape: CIRCLE
      - size: 50

      color: GREEN size: 20 shape: TRIANGLE posn: 20,40
      ['color:', 'GREEN', 'size:', '20', 'shape:', 'TRIANGLE', 'posn:', ['20', ',', '40']]
      - color: GREEN
      - posn: ['20', ',', '40']
        - x: 20
        - y: 40
      - shape: TRIANGLE
      - size: 20

  checkRecursion(parseElementList)
  parseImpl(instring, loc, doActions=True)
  streamline()

class pyparsing.Empty

  Bases: `pyparsing.Token`

  An empty token, will always match.

class pyparsing.FollowedBy(expr)

  Bases: `pyparsing.ParseElementEnhance`

  Lookahead matching of the given parse expression. `FollowedBy` does not advance the parsing position within the input string, it only verifies that the specified parse expression matches at the current position. `FollowedBy` always returns a null token list. If any results names are defined in the lookahead expression, those will be returned for access by name.

  Example:

      # use FollowedBy to match a label only if it is followed by a ':'
      data_word = Word(alphas)
      label = data_word + FollowedBy(':')
      attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))

      OneOrMore(attr_expr).parseString("shape: SQUARE color: BLACK posn: upper left").pprint()

  prints:

      [['shape', 'SQUARE'], ['color', 'BLACK'], ['posn', 'upper left']]

  parseImpl(instring, loc, doActions=True)

class pyparsing.Forward(other=None)

  Bases: `pyparsing.ParseElementEnhance`

  Forward declaration of an expression to be defined later - used for recursive grammars, such as algebraic infix notation. When the expression is known, it is assigned to the `Forward` variable using the ‘<<’ operator.

  Note: take care when assigning to `Forward` not to overlook precedence of operators.

  Specifically, ‘|’ has a lower precedence than ‘<<’, so that:

      fwdExpr << a | b | c

  will actually be evaluated as:

      (fwdExpr << a) | b | c

  thereby leaving b and c out as parseable alternatives. It is recommended that you explicitly group the values inserted into the `Forward`:

      fwdExpr << (a | b | c)

  Converting to use the ‘<<=’ operator instead will avoid this problem.

  See `ParseResults.pprint` for an example of a recursive parser created using `Forward`.

  copy()

    Make a copy of this `ParserElement`. Useful for defining different parse actions for the same parsing pattern, using copies of the original parse element.

    Example:

        integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
        integerK = integer.copy().addParseAction(lambda toks: toks[0] * 1024) + Suppress("K")
        integerM = integer.copy().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

        print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M"))

    prints:

        [5120, 100, 655360, 268435456]

    Equivalent form of `expr.copy()` is just `expr()`:

        integerM = integer().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

  leaveWhitespace()

    Disables the skipping of whitespace before matching the characters in the `ParserElement`’s defined pattern. This is normally only used internally by the pyparsing module, but may be needed in some whitespace-sensitive grammars.

  streamline()
  validate(validateTrace=None)

    Check defined expressions for valid structure, check for infinite recursive definitions.

class pyparsing.GoToColumn(colno)

  Bases: `pyparsing._PositionToken`

  Token to advance to a specific column of input text; useful for tabular report scraping.

  parseImpl(instring, loc, doActions=True)
  preParse(instring, loc)

class pyparsing.Group(expr)

  Bases: `pyparsing.TokenConverter`

  Converter to return the matched tokens as a list - useful for returning tokens of `ZeroOrMore` and `OneOrMore` expressions.

  Example:

      ident = Word(alphas)
      num = Word(nums)
      term = ident | num
      func = ident + Optional(delimitedList(term))
      print(func.parseString("fn a, b, 100"))  # -> ['fn', 'a', 'b', '100']

      func = ident + Group(Optional(delimitedList(term)))
      print(func.parseString("fn a, b, 100"))  # -> ['fn', ['a', 'b', '100']]

  postParse(instring, loc, tokenlist)

class pyparsing.Keyword(matchString, identChars=None, caseless=False)

  Bases: `pyparsing.Token`

  Token to exactly match a specified string as a keyword, that is, it must be immediately followed by a non-keyword character. Compare with `Literal`:

  > - `Literal("if")` will match the leading `'if'` in `'ifAndOnlyIf'`.

  > - `Keyword("if")` will not; it will only match the leading `'if'` in `'if x=1'`, or `'if(y==2)'`

  Accepts two optional constructor arguments in addition to the keyword string:

  > - `identChars` is a string of characters that would be valid identifier characters, defaulting to all alphanumerics + “_” and “$”

  > - `caseless` allows case-insensitive matching, default is `False`.

  Example:

      Keyword("start").parseString("start")  # -> ['start']
      Keyword("start").parseString("starting")  # -> Exception

  For case-insensitive matching, use `CaselessKeyword`.

  DEFAULT_KEYWORD_CHARS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_$'
  copy()

    Make a copy of this `ParserElement`. Useful for defining different parse actions for the same parsing pattern, using copies of the original parse element.

    Example:

        integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
        integerK = integer.copy().addParseAction(lambda toks: toks[0] * 1024) + Suppress("K")
        integerM = integer.copy().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

        print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M"))

    prints:

        [5120, 100, 655360, 268435456]

    Equivalent form of `expr.copy()` is just `expr()`:

        integerM = integer().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

  parseImpl(instring, loc, doActions=True)
  static setDefaultKeywordChars(chars)

    Overrides the default Keyword chars

class pyparsing.LineEnd

  Bases: `pyparsing._PositionToken`

  Matches if current position is at the end of a line within the parse string

  parseImpl(instring, loc, doActions=True)

class pyparsing.LineStart

  Bases: `pyparsing._PositionToken`

  Matches if current position is at the beginning of a line within the parse string

  Example:

      test = '''\
      AAA this line
      AAA and this line
        AAA but not this one
      B AAA and definitely not this one
      '''

      for t in (LineStart() + 'AAA' + restOfLine).searchString(test):
          print(t)

  prints:

      ['AAA', ' this line']
      ['AAA', ' and this line']

  parseImpl(instring, loc, doActions=True)

class pyparsing.Literal(matchString)

  Bases: `pyparsing.Token`

  Token to exactly match a specified string.

  Example:

      Literal('blah').parseString('blah')  # -> ['blah']
      Literal('blah').parseString('blahfooblah')  # -> ['blah']
      Literal('blah').parseString('bla')  # -> Exception: Expected "blah"

  For case-insensitive matching, use `CaselessLiteral`.

  For keyword matching (force word break before and after the matched string), use `Keyword` or `CaselessKeyword`.

  parseImpl(instring, loc, doActions=True)

class pyparsing.MatchFirst(exprs, savelist=False)

  Bases: `pyparsing.ParseExpression`

  Requires that at least one `ParseExpression` is found. If two expressions match, the first one listed is the one that will match. May be constructed using the `'|'` operator.

  Example:

      # construct MatchFirst using '|' operator

      # watch the order of expressions to match
      number = Word(nums) | Combine(Word(nums) + '.' + Word(nums))
      print(number.searchString("123 3.1416 789")) #  Fail! -> [['123'], ['3'], ['1416'], ['789']]

      # put more selective expression first
      number = Combine(Word(nums) + '.' + Word(nums)) | Word(nums)
      print(number.searchString("123 3.1416 789")) #  Better -> [['123'], ['3.1416'], ['789']]

  checkRecursion(parseElementList)
  parseImpl(instring, loc, doActions=True)
  streamline()

class pyparsing.NoMatch

  Bases: `pyparsing.Token`

  A token that will never match.

  parseImpl(instring, loc, doActions=True)

class pyparsing.NotAny(expr)

  Bases: `pyparsing.ParseElementEnhance`

  Lookahead to disallow matching with the given parse expression. `NotAny` does not advance the parsing position within the input string, it only verifies that the specified parse expression does not match at the current position. Also, `NotAny` does not skip over leading whitespace. `NotAny` always returns a null token list. May be constructed using the ‘~’ operator.

  Example:

      AND, OR, NOT = map(CaselessKeyword, "AND OR NOT".split())

      # take care not to mistake keywords for identifiers
      ident = ~(AND | OR | NOT) + Word(alphas)
      boolean_term = Optional(NOT) + ident

      # very crude boolean expression - to support parenthesis groups and
      # operation hierarchy, use infixNotation
      boolean_expr = boolean_term + ZeroOrMore((AND | OR) + boolean_term)

      # integers that are followed by "." are actually floats
      integer = Word(nums) + ~Char(".")

  parseImpl(instring, loc, doActions=True)

class pyparsing.OneOrMore(expr, stopOn=None)

  Bases: `pyparsing._MultipleMatch`

  Repetition of one or more of the given expression.

  Parameters:

    - expr - expression that must match one or more times

    - stopOn - (default= `None`) - expression for a terminating sentinel

        (only required if the sentinel would ordinarily match the repetition expression)

  Example:

      data_word = Word(alphas)
      label = data_word + FollowedBy(':')
      attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join))

      text = "shape: SQUARE posn: upper left color: BLACK"
      OneOrMore(attr_expr).parseString(text).pprint()  # Fail! read 'color' as data instead of next label -> [['shape', 'SQUARE color']]

      # use stopOn attribute for OneOrMore to avoid reading label string as part of the data
      attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
      OneOrMore(attr_expr).parseString(text).pprint() # Better -> [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']]

      # could also be written as
      (attr_expr * (1,)).parseString(text).pprint()

class pyparsing.OnlyOnce(methodCall)

  Bases: `object`

  Wrapper for parse actions, to ensure they are only called once.

  reset()

class pyparsing.Optional(expr, default=<pyparsing._NullToken object>)

  Bases: `pyparsing.ParseElementEnhance`

  Optional matching of the given expression.

  Parameters:

    - expr - expression that must match zero or more times

    - default (optional) - value to be returned if the optional expression is not found.

  Example:

      # US postal code can be a 5-digit zip, plus optional 4-digit qualifier
      zip = Combine(Word(nums, exact=5) + Optional('-' + Word(nums, exact=4)))
      zip.runTests('''
          # traditional ZIP code
          12345

          # ZIP+4 form
          12101-0001

          # invalid ZIP
          98765-
          ''')

  prints:

      # traditional ZIP code
      12345
      ['12345']

      # ZIP+4 form
      12101-0001
      ['12101-0001']

      # invalid ZIP
      98765-
           ^
      FAIL: Expected end of text (at char 5), (line:1, col:6)

  parseImpl(instring, loc, doActions=True)

class pyparsing.Or(exprs, savelist=False)

  Bases: `pyparsing.ParseExpression`

  Requires that at least one `ParseExpression` is found. If two expressions match, the expression that matches the longest string will be used. May be constructed using the `'^'` operator.

  Example:

      # construct Or using '^' operator

      number = Word(nums) ^ Combine(Word(nums) + '.' + Word(nums))
      print(number.searchString("123 3.1416 789"))

  prints:

      [['123'], ['3.1416'], ['789']]

  checkRecursion(parseElementList)
  parseImpl(instring, loc, doActions=True)
  streamline()

exception pyparsing.ParseBaseException(pstr, loc=0, msg=None, elem=None)

  Bases: `Exception`

  base exception class for all parsing runtime exceptions

  markInputline(markerString='>!<')

    Extracts the exception line from the input string, and marks the location of the exception with a special symbol.

class pyparsing.ParseElementEnhance(expr, savelist=False)

  Bases: `pyparsing.ParserElement`

  Abstract subclass of `ParserElement`, for combining and post-processing parsed tokens.

  checkRecursion(parseElementList)
  ignore(other)

    Define expression to be ignored (e.g., comments) while doing pattern matching; may be called repeatedly, to define multiple comment or other ignorable patterns.

    Example:

        patt = OneOrMore(Word(alphas))
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj']

        patt.ignore(cStyleComment)
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd']

  leaveWhitespace()

    Disables the skipping of whitespace before matching the characters in the `ParserElement`’s defined pattern. This is normally only used internally by the pyparsing module, but may be needed in some whitespace-sensitive grammars.

  parseImpl(instring, loc, doActions=True)
  streamline()
  validate(validateTrace=None)

    Check defined expressions for valid structure, check for infinite recursive definitions.

exception pyparsing.ParseException(pstr, loc=0, msg=None, elem=None)

  Bases: `pyparsing.ParseBaseException`

  Exception thrown when parse expressions don’t match class; supported attributes by name are: - lineno - returns the line number of the exception text - col - returns the column number of the exception text - line - returns the line containing the exception text

  Example:

      try:
          Word(nums).setName("integer").parseString("ABC")
      except ParseException as pe:
          print(pe)
          print("column: {}".format(pe.col))

  prints:

      Expected integer (at char 0), (line:1, col:1)
       column: 1

  static explain(exc, depth=16)

    Method to take an exception and translate the Python internal traceback into a list of the pyparsing expressions that caused the exception to be raised.

    Parameters:

    > - exc - exception raised during parsing (need not be a ParseException, in support of Python exceptions that might be raised in a parse action)

    > - depth (default=16) - number of levels back in the stack trace to list expression and function names; if None, the full stack trace names will be listed; if 0, only the failing input line, marker, and exception string will be shown

    Returns a multi-line string listing the ParserElements and/or function names in the exception’s stack trace.

    Note: the diagnostic output will include string representations of the expressions that failed to parse. These representations will be more helpful if you use setName to give identifiable names to your expressions. Otherwise they will use the default string forms, which may be cryptic to read.

    explain() is only supported under Python 3.

class pyparsing.ParseExpression(exprs, savelist=False)

  Bases: `pyparsing.ParserElement`

  Abstract subclass of ParserElement, for combining and post-processing parsed tokens.

  append(other)
  copy()

    Make a copy of this `ParserElement`. Useful for defining different parse actions for the same parsing pattern, using copies of the original parse element.

    Example:

        integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
        integerK = integer.copy().addParseAction(lambda toks: toks[0] * 1024) + Suppress("K")
        integerM = integer.copy().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

        print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M"))

    prints:

        [5120, 100, 655360, 268435456]

    Equivalent form of `expr.copy()` is just `expr()`:

        integerM = integer().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

  ignore(other)

    Define expression to be ignored (e.g., comments) while doing pattern matching; may be called repeatedly, to define multiple comment or other ignorable patterns.

    Example:

        patt = OneOrMore(Word(alphas))
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj']

        patt.ignore(cStyleComment)
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd']

  leaveWhitespace()

    Extends `leaveWhitespace` defined in base class, and also invokes `leaveWhitespace` on all contained expressions.

  streamline()
  validate(validateTrace=None)

    Check defined expressions for valid structure, check for infinite recursive definitions.

exception pyparsing.ParseFatalException(pstr, loc=0, msg=None, elem=None)

  Bases: `pyparsing.ParseBaseException`

  user-throwable exception thrown when inconsistent parse content is found; stops all parsing immediately

class pyparsing.ParseResults(toklist=None, name=None, asList=True, modal=True)

  Bases: `object`

  Structured parse results, to provide multiple means of access to the parsed data:

  > - as a list (`len(results)`)

  > - by list index (`results[0], results[1]`, etc.)

  > - by attribute (`results.<resultsName>` - see `ParserElement.setResultsName`)

  Example:

      integer = Word(nums)
      date_str = (integer.setResultsName("year") + '/'
                      + integer.setResultsName("month") + '/'
                      + integer.setResultsName("day"))
      # equivalent form:
      # date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

      # parseString returns a ParseResults object
      result = date_str.parseString("1999/12/31")

      def test(s, fn=repr):
          print("%s -> %s" % (s, fn(eval(s))))
      test("list(result)")
      test("result[0]")
      test("result['month']")
      test("result.day")
      test("'month' in result")
      test("'minutes' in result")
      test("result.dump()", str)

  prints:

      list(result) -> ['1999', '/', '12', '/', '31']
      result[0] -> '1999'
      result['month'] -> '12'
      result.day -> '31'
      'month' in result -> True
      'minutes' in result -> False
      result.dump() -> ['1999', '/', '12', '/', '31']
      - day: 31
      - month: 12
      - year: 1999

  append(item)

    Add single element to end of ParseResults list of elements.

    Example:

        print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']

        # use a parse action to compute the sum of the parsed integers, and add it to the end
        def append_sum(tokens):
            tokens.append(sum(map(int, tokens)))
        print(OneOrMore(Word(nums)).addParseAction(append_sum).parseString("0 123 321")) # -> ['0', '123', '321', 444]

  asDict()

    Returns the named parse results as a nested dictionary.

    Example:

        integer = Word(nums)
        date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

        result = date_str.parseString('12/31/1999')
        print(type(result), repr(result)) # -> <class 'pyparsing.ParseResults'> (['12', '/', '31', '/', '1999'], {'day': [('1999', 4)], 'year': [('12', 0)], 'month': [('31', 2)]})

        result_dict = result.asDict()
        print(type(result_dict), repr(result_dict)) # -> <class 'dict'> {'day': '1999', 'year': '12', 'month': '31'}

        # even though a ParseResults supports dict-like access, sometime you just need to have a dict
        import json
        print(json.dumps(result)) # -> Exception: TypeError: ... is not JSON serializable
        print(json.dumps(result.asDict())) # -> {"month": "31", "day": "1999", "year": "12"}

  asList()

    Returns the parse results as a nested list of matching tokens, all converted to strings.

    Example:

        patt = OneOrMore(Word(alphas))
        result = patt.parseString("sldkj lsdkj sldkj")
        # even though the result prints in string-like form, it is actually a pyparsing ParseResults
        print(type(result), result) # -> <class 'pyparsing.ParseResults'> ['sldkj', 'lsdkj', 'sldkj']

        # Use asList() to create an actual list
        result_list = result.asList()
        print(type(result_list), result_list) # -> <class 'list'> ['sldkj', 'lsdkj', 'sldkj']

  asXML(doctag=None, namedItemsOnly=False, indent='', formatted=True)

    (Deprecated) Returns the parse results as XML. Tags are created for tokens and lists that have defined results names.

  clear()

    Clear all elements and results names.

  copy()

    Returns a new copy of a `ParseResults` object.

  dump(indent='', full=True, include_list=True, _depth=0)

    Diagnostic method for listing out the contents of a `ParseResults`. Accepts an optional `indent` argument so that this string can be embedded in a nested display of other data.

    Example:

        integer = Word(nums)
        date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

        result = date_str.parseString('12/31/1999')
        print(result.dump())

    prints:

        ['12', '/', '31', '/', '1999']
        - day: 1999
        - month: 31
        - year: 12

  extend(itemseq)

    Add sequence of elements to end of ParseResults list of elements.

    Example:

        patt = OneOrMore(Word(alphas))

        # use a parse action to append the reverse of the matched strings, to make a palindrome
        def make_palindrome(tokens):
            tokens.extend(reversed([t[::-1] for t in tokens]))
            return ''.join(tokens)
        print(patt.addParseAction(make_palindrome).parseString("lskdj sdlkjf lksd")) # -> 'lskdjsdlkjflksddsklfjkldsjdksl'

  classmethod from_dict(other, name=None)

    Helper classmethod to construct a ParseResults from a dict, preserving the name-value relations as results names. If an optional ‘name’ argument is given, a nested ParseResults will be returned

  get(key, defaultValue=None)

    Returns named result matching the given key, or if there is no such name, then returns the given `defaultValue` or `None` if no `defaultValue` is specified.

    Similar to `dict.get()`.

    Example:

        integer = Word(nums)
        date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

        result = date_str.parseString("1999/12/31")
        print(result.get("year")) # -> '1999'
        print(result.get("hour", "not specified")) # -> 'not specified'
        print(result.get("hour")) # -> None

  getName()

    Returns the results name for this token expression. Useful when several different expressions might match at a particular location.

    Example:

        integer = Word(nums)
        ssn_expr = Regex(r"\d\d\d-\d\d-\d\d\d\d")
        house_number_expr = Suppress('#') + Word(nums, alphanums)
        user_data = (Group(house_number_expr)("house_number")
                    | Group(ssn_expr)("ssn")
                    | Group(integer)("age"))
        user_info = OneOrMore(user_data)

        result = user_info.parseString("22 111-22-3333 #221B")
        for item in result:
            print(item.getName(), ':', item[0])

    prints:

        age : 22
        ssn : 111-22-3333
        house_number : 221B

  haskeys()

    Since keys() returns an iterator, this method is helpful in bypassing code that looks for the existence of any defined results names.

  insert(index, insStr)

    Inserts new element at location index in the list of parsed tokens.

    Similar to `list.insert()`.

    Example:

        print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']

        # use a parse action to insert the parse location in the front of the parsed results
        def insert_locn(locn, tokens):
            tokens.insert(0, locn)
        print(OneOrMore(Word(nums)).addParseAction(insert_locn).parseString("0 123 321")) # -> [0, '0', '123', '321']

  items()

    Returns an iterator of all named result key-value tuples.

  iteritems

    Returns an iterator of all named result key-value tuples (Python 2.x only).

  iterkeys

    Returns an iterator of all named result keys (Python 2.x only).

  itervalues

    Returns an iterator of all named result values (Python 2.x only).

  keys()

    Returns an iterator of all named result keys.

  pop(*args, **kwargs)

    Removes and returns item at specified index (default= `last`). Supports both `list` and `dict` semantics for `pop()`. If passed no argument or an integer argument, it will use `list` semantics and pop tokens from the list of parsed tokens. If passed a non-integer argument (most likely a string), it will use `dict` semantics and pop the corresponding value from any defined results names. A second default return value argument is supported, just as in `dict.pop()`.

    Example:

        def remove_first(tokens):
            tokens.pop(0)
        print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
        print(OneOrMore(Word(nums)).addParseAction(remove_first).parseString("0 123 321")) # -> ['123', '321']

        label = Word(alphas)
        patt = label("LABEL") + OneOrMore(Word(nums))
        print(patt.parseString("AAB 123 321").dump())

        # Use pop() in a parse action to remove named result (note that corresponding value is not
        # removed from list form of results)
        def remove_LABEL(tokens):
            tokens.pop("LABEL")
            return tokens
        patt.addParseAction(remove_LABEL)
        print(patt.parseString("AAB 123 321").dump())

    prints:

        ['AAB', '123', '321']
        - LABEL: AAB

        ['AAB', '123', '321']

  pprint(*args, **kwargs)

    Pretty-printer for parsed results as a list, using the pprint module. Accepts additional positional or keyword args as defined for pprint.pprint .

    Example:

        ident = Word(alphas, alphanums)
        num = Word(nums)
        func = Forward()
        term = ident | num | Group('(' + func + ')')
        func <<= ident + Group(Optional(delimitedList(term)))
        result = func.parseString("fna a,b,(fnb c,d,200),100")
        result.pprint(width=40)

    prints:

        ['fna',
         ['a',
          'b',
          ['(', 'fnb', ['c', 'd', '200'], ')'],
          '100']]

  values()

    Returns an iterator of all named result values.

exception pyparsing.ParseSyntaxException(pstr, loc=0, msg=None, elem=None)

  Bases: `pyparsing.ParseFatalException`

  just like `ParseFatalException`, but thrown internally when an `ErrorStop` (‘-’ operator) indicates that parsing is to stop immediately because an unbacktrackable syntax error has been found.

class pyparsing.ParserElement(savelist=False)

  Bases: `object`

  Abstract base level parser element class.

  DEFAULT_WHITE_CHARS = ' \n\t\r'
  addCondition(*fns, **kwargs)

    Add a boolean predicate function to expression’s list of parse actions. See `setParseAction` for function call signatures. Unlike `setParseAction`, functions passed to `addCondition` need to return boolean success/fail of the condition.

    Optional keyword arguments: - message = define a custom message to be used in the raised exception - fatal = if True, will raise ParseFatalException to stop parsing immediately; otherwise will raise ParseException

    Example:

        integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
        year_int = integer.copy()
        year_int.addCondition(lambda toks: toks[0] >= 2000, message="Only support years 2000 and later")
        date_str = year_int + '/' + integer + '/' + integer

        result = date_str.parseString("1999/12/31")  # -> Exception: Only support years 2000 and later (at char 0), (line:1, col:1)

  addParseAction(*fns, **kwargs)

    Add one or more parse actions to expression’s list of parse actions. See `setParseAction`.

    See examples in `copy`.

  canParseNext(instring, loc)
  checkRecursion(parseElementList)
  copy()

    Make a copy of this `ParserElement`. Useful for defining different parse actions for the same parsing pattern, using copies of the original parse element.

    Example:

        integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
        integerK = integer.copy().addParseAction(lambda toks: toks[0] * 1024) + Suppress("K")
        integerM = integer.copy().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

        print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M"))

    prints:

        [5120, 100, 655360, 268435456]

    Equivalent form of `expr.copy()` is just `expr()`:

        integerM = integer().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")

  static enablePackrat(cache_size_limit=128)

    Enables “packrat” parsing, which adds memoizing to the parsing logic. Repeated parse attempts at the same string location (which happens often in many complex grammars) can immediately return a cached value, instead of re-executing parsing/validating code. Memoizing is done of both valid results and parsing exceptions.

    Parameters:

    - cache_size_limit - (default= `128`) - if an integer value is provided will limit the size of the packrat cache; if None is passed, then the cache size will be unbounded; if 0 is passed, the cache will be effectively disabled.

    This speedup may break existing programs that use parse actions that have side-effects. For this reason, packrat parsing is disabled when you first import pyparsing. To activate the packrat feature, your program must call the class method `ParserElement.enablePackrat`. For best results, call `enablePackrat()` immediately after importing pyparsing.

    Example:

        import pyparsing
        pyparsing.ParserElement.enablePackrat()

  ignore(other)

    Define expression to be ignored (e.g., comments) while doing pattern matching; may be called repeatedly, to define multiple comment or other ignorable patterns.

    Example:

        patt = OneOrMore(Word(alphas))
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj']

        patt.ignore(cStyleComment)
        patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd']

  static inlineLiteralsUsing(cls)

    Set class to be used for inclusion of string literals into a parser.

    Example:

        # default literal class used is Literal
        integer = Word(nums)
        date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

        date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']

        # change to Suppress
        ParserElement.inlineLiteralsUsing(Suppress)
        date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

        date_str.parseString("1999/12/31")  # -> ['1999', '12', '31']

  leaveWhitespace()

    Disables the skipping of whitespace before matching the characters in the `ParserElement`’s defined pattern. This is normally only used internally by the pyparsing module, but may be needed in some whitespace-sensitive grammars.

  matches(testString, parseAll=True)

    Method for quick testing of a parser against a test string. Good for simple inline microtests of sub expressions while building up larger parser.

    Parameters:

      - testString - to test against this expression for a match

      - parseAll - (default= `True`) - flag to pass to `parseString` when running tests

    Example:

        expr = Word(nums)
        assert expr.matches("100")

  packrat_cache = {}
  packrat_cache_lock = <unlocked _thread.RLock object owner=0 count=0>
  packrat_cache_stats = [0, 0]
  parseFile(file_or_filename, parseAll=False)

    Execute the parse expression on the given file or filename. If a filename is specified (instead of a file object), the entire file is opened, read, and closed before parsing.

  parseImpl(instring, loc, doActions=True)
  parseString(instring, parseAll=False)

    Execute the parse expression with the given string. This is the main interface to the client code, once the complete expression has been built.

    Returns the parsed data as a `ParseResults` object, which may be accessed as a list, or as a dict or object with attributes if the given parser includes results names.

    If you want the grammar to require that the entire input string be successfully parsed, then set `parseAll` to True (equivalent to ending the grammar with `StringEnd()`).

    Note: `parseString` implicitly calls `expandtabs()` on the input string, in order to report proper column numbers in parse actions. If the input string contains tabs and the grammar uses parse actions that use the `loc` argument to index into the string being parsed, you can ensure you have a consistent view of the input string by:

    - calling `parseWithTabs` on your grammar before calling `parseString` (see `parseWithTabs`)

    - define your parse action using the full `(s, loc, toks)` signature, and reference the input string using the parse action’s `s` argument

    - explictly expand the tabs in your input string before calling `parseString`

    Example:

        Word('a').parseString('aaaaabaaa')  # -> ['aaaaa']
        Word('a').parseString('aaaaabaaa', parseAll=True)  # -> Exception: Expected end of text

  parseWithTabs()

    Overrides default behavior to expand `<TAB>``s to spaces before parsing the input string. Must be called before ``parseString` when the input grammar contains elements that match `<TAB>` characters.

  postParse(instring, loc, tokenlist)
  preParse(instring, loc)
  static resetCache()
  runTests(tests, parseAll=True, comment='#', fullDump=True, printResults=True, failureTests=False, postParse=None, file=None)

    Execute the parse expression on a series of test strings, showing each test, the parsed results or where the parse failed. Quick and easy way to run a parse expression against a list of sample strings.

    Parameters:

      - tests - a list of separate test strings, or a multiline string of test strings

      - parseAll - (default= `True`) - flag to pass to `parseString` when running tests

      - comment - (default= `'#'`) - expression for indicating embedded comments in the test

          string; pass None to disable comment filtering

      - fullDump - (default= `True`) - dump results as list followed by results names in nested outline;

          if False, only dump nested list

      - printResults - (default= `True`) prints test output to stdout

      - failureTests - (default= `False`) indicates if these tests are expected to fail parsing

      - postParse - (default= `None`) optional callback for successful parse results; called as

          fn(test_string, parse_results) and returns a string to be added to the test output

      - file - (default=``None``) optional file-like object to which test output will be written;

          if None, will default to `sys.stdout`

    Returns: a (success, results) tuple, where success indicates that all tests succeeded (or failed if `failureTests` is True), and the results contain a list of lines of each test’s output

    Example:

        number_expr = pyparsing_common.number.copy()

        result = number_expr.runTests('''
            # unsigned integer
            100
            # negative integer
            -100
            # float with scientific notation
            6.02e23
            # integer with scientific notation
            1e-12
            ''')
        print("Success" if result[0] else "Failed!")

        result = number_expr.runTests('''
            # stray character
            100Z
            # missing leading digit before '.'
            -.100
            # too many '.'
            3.14.159
            ''', failureTests=True)
        print("Success" if result[0] else "Failed!")

    prints:

        # unsigned integer
        100
        [100]

        # negative integer
        -100
        [-100]

        # float with scientific notation
        6.02e23
        [6.02e+23]

        # integer with scientific notation
        1e-12
        [1e-12]

        Success

        # stray character
        100Z
           ^
        FAIL: Expected end of text (at char 3), (line:1, col:4)

        # missing leading digit before '.'
        -.100
        ^
        FAIL: Expected {real number with scientific notation | real number | signed integer} (at char 0), (line:1, col:1)

        # too many '.'
        3.14.159
            ^
        FAIL: Expected end of text (at char 4), (line:1, col:5)

        Success

    Each test string must be on a single line. If you want to test a string that spans multiple lines, create a test like this:

        expr.runTest(r"this is a test\n of strings that spans \n 3 lines")

    (Note that this is a raw string literal, you must include the leading ‘r’.)

  scanString(instring, maxMatches=9223372036854775807, overlap=False)

    Scan the input string for expression matches. Each match will return the matching tokens, start location, and end location. May be called with optional `maxMatches` argument, to clip scanning after ‘n’ matches are found. If `overlap` is specified, then overlapping matches will be reported.

    Note that the start and end locations are reported relative to the string being parsed. See `parseString` for more information on parsing strings with embedded tabs.

    Example:

        source = "sldjf123lsdjjkf345sldkjf879lkjsfd987"
        print(source)
        for tokens, start, end in Word(alphas).scanString(source):
            print(' '*start + '^'*(end-start))
            print(' '*start + tokens[0])

    prints:

        sldjf123lsdjjkf345sldkjf879lkjsfd987
        ^^^^^
        sldjf
                ^^^^^^^
                lsdjjkf
                          ^^^^^^
                          sldkjf
                                   ^^^^^^
                                   lkjsfd

  searchString(instring, maxMatches=9223372036854775807)

    Another extension to `scanString`, simplifying the access to the tokens found to match the given parse expression. May be called with optional `maxMatches` argument, to clip searching after ‘n’ matches are found.

    Example:

        # a capitalized word starts with an uppercase letter, followed by zero or more lowercase letters
        cap_word = Word(alphas.upper(), alphas.lower())

        print(cap_word.searchString("More than Iron, more than Lead, more than Gold I need Electricity"))

        # the sum() builtin can be used to merge results into a single ParseResults object
        print(sum(cap_word.searchString("More than Iron, more than Lead, more than Gold I need Electricity")))

    prints:

        [['More'], ['Iron'], ['Lead'], ['Gold'], ['I'], ['Electricity']]
        ['More', 'Iron', 'Lead', 'Gold', 'I', 'Electricity']

  setBreak(breakFlag=True)

    Method to invoke the Python pdb debugger when this element is about to be parsed. Set `breakFlag` to True to enable, False to disable.

  setDebug(flag=True)

    Enable display of debugging messages while doing pattern matching. Set `flag` to True to enable, False to disable.

    Example:

        wd = Word(alphas).setName("alphaword")
        integer = Word(nums).setName("numword")
        term = wd | integer

        # turn on debugging for wd
        wd.setDebug()

        OneOrMore(term).parseString("abc 123 xyz 890")

    prints:

        Match alphaword at loc 0(1,1)
        Matched alphaword -> ['abc']
        Match alphaword at loc 3(1,4)
        Exception raised:Expected alphaword (at char 4), (line:1, col:5)
        Match alphaword at loc 7(1,8)
        Matched alphaword -> ['xyz']
        Match alphaword at loc 11(1,12)
        Exception raised:Expected alphaword (at char 12), (line:1, col:13)
        Match alphaword at loc 15(1,16)
        Exception raised:Expected alphaword (at char 15), (line:1, col:16)

    The output shown is that produced by the default debug actions - custom debug actions can be specified using `setDebugActions`. Prior to attempting to match the `wd` expression, the debugging message `"Match <exprname> at loc <n>(<line>,<col>)"` is shown. Then if the parse succeeds, a `"Matched"` message is shown, or an `"Exception raised"` message is shown. Also note the use of `setName` to assign a human-readable name to the expression, which makes debugging and exception messages easier to understand - for instance, the default name created for the `Word` expression without calling `setName` is `"W:(ABCD...)"`.

  setDebugActions(startAction, successAction, exceptionAction)

    Enable display of debugging messages while doing pattern matching.

  static setDefaultWhitespaceChars(chars)

    Overrides the default whitespace chars

    Example:

        # default whitespace chars are space, <TAB> and newline
        OneOrMore(Word(alphas)).parseString("abc def\nghi jkl")  # -> ['abc', 'def', 'ghi', 'jkl']

        # change to just treat newline as significant
        ParserElement.setDefaultWhitespaceChars(" \t")
        OneOrMore(Word(alphas)).parseString("abc def\nghi jkl")  # -> ['abc', 'def']

  setFailAction(fn)

    Define action to perform if parsing fails at this expression. Fail acton fn is a callable function that takes the arguments `fn(s, loc, expr, err)` where: - s = string being parsed - loc = location where expression match was attempted and failed - expr = the parse expression that failed - err = the exception thrown The function returns no value. It may throw `ParseFatalException` if it is desired to stop parsing immediately.

  setName(name)

    Define name for this expression, makes debugging and exception messages clearer.

    Example:

        Word(nums).parseString("ABC")  # -> Exception: Expected W:(0123...) (at char 0), (line:1, col:1)
        Word(nums).setName("integer").parseString("ABC")  # -> Exception: Expected integer (at char 0), (line:1, col:1)

  setParseAction(*fns, **kwargs)

    Define one or more actions to perform when successfully matching parse element definition. Parse action fn is a callable method with 0-3 arguments, called as `fn(s, loc, toks)` , `fn(loc, toks)` , `fn(toks)` , or just `fn()` , where:

    - s = the original string being parsed (see note below)

    - loc = the location of the matching substring

    - toks = a list of the matched tokens, packaged as a `ParseResults` object

    If the functions in fns modify the tokens, they can return them as the return value from fn, and the modified list of tokens will replace the original. Otherwise, fn does not need to return any value.

    If None is passed as the parse action, all previously added parse actions for this expression are cleared.

    Optional keyword arguments: - callDuringTry = (default= `False`) indicate if parse action should be run during lookaheads and alternate testing

    Note: the default parsing behavior is to expand tabs in the input string before starting the parsing process. See `parseString for more information on parsing strings containing ``<TAB>`` s, and suggested methods to maintain a consistent view of the parsed string, the parse location, and line and column positions within the parsed string.

    Example:

        integer = Word(nums)
        date_str = integer + '/' + integer + '/' + integer

        date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']

        # use parse action to convert to ints at parse time
        integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
        date_str = integer + '/' + integer + '/' + integer

        # note that integer fields are now ints, not strings
        date_str.parseString("1999/12/31")  # -> [1999, '/', 12, '/', 31]

  setResultsName(name, listAllMatches=False)

    Define name for referencing matching tokens as a nested attribute of the returned parse results. NOTE: this returns a copy of the original `ParserElement` object; this is so that the client can define a basic element, such as an integer, and reference it in multiple places with different names.

    You can also set results names using the abbreviated syntax, `expr("name")` in place of `expr.setResultsName("name")` - see `__call__`.

    Example:

        date_str = (integer.setResultsName("year") + '/'
                    + integer.setResultsName("month") + '/'
                    + integer.setResultsName("day"))

        # equivalent form:
        date_str = integer("year") + '/' + integer("month") + '/' + integer("day")

  setWhitespaceChars(chars)

    Overrides the default whitespace chars

  split(instring, maxsplit=9223372036854775807, includeSeparators=False)

    Generator method to split a string using the given expression as a separator. May be called with optional `maxsplit` argument, to limit the number of splits; and the optional `includeSeparators` argument (default= `False`), if the separating matching text should be included in the split results.

    Example:

        punc = oneOf(list(".,;:/-!?"))
        print(list(punc.split("This, this?, this sentence, is badly punctuated!")))

    prints:

        ['This', ' this', '', ' this sentence', ' is badly punctuated', '']

  streamline()
  suppress()

    Suppresses the output of this `ParserElement`; useful to keep punctuation from cluttering up returned output.

  transformString(instring)

    Extension to `scanString`, to modify matching text with modified tokens that may be returned from a parse action. To use `transformString`, define a grammar and attach a parse action to it that modifies the returned token list. Invoking `transformString()` on a target string will then scan for matches, and replace the matched text patterns according to the logic in the parse action. `transformString()` returns the resulting transformed string.

    Example:

        wd = Word(alphas)
        wd.setParseAction(lambda toks: toks[0].title())

        print(wd.transformString("now is the winter of our discontent made glorious summer by this sun of york."))

    prints:

        Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York.

  tryParse(instring, loc)
  validate(validateTrace=None)

    Check defined expressions for valid structure, check for infinite recursive definitions.

  verbose_stacktrace = False

class pyparsing.PrecededBy(expr, retreat=None)

  Bases: `pyparsing.ParseElementEnhance`

  Lookbehind matching of the given parse expression. `PrecededBy` does not advance the parsing position within the input string, it only verifies that the specified parse expression matches prior to the current position. `PrecededBy` always returns a null token list, but if a results name is defined on the given expression, it is returned.

  Parameters:

  > - expr - expression that must match prior to the current parse location

  > - retreat - (default= `None`) - (int) maximum number of characters to lookbehind prior to the current parse location

  If the lookbehind expression is a string, Literal, Keyword, or a Word or CharsNotIn with a specified exact or maximum length, then the retreat parameter is not required. Otherwise, retreat must be specified to give a maximum number of characters to look back from the current parse position for a lookbehind match.

  Example:

      # VB-style variable names with type prefixes
      int_var = PrecededBy("#") + pyparsing_common.identifier
      str_var = PrecededBy("$") + pyparsing_common.identifier

  parseImpl(instring, loc=0, doActions=True)

class pyparsing.QuotedString(quoteChar, escChar=None, escQuote=None, multiline=False, unquoteResults=True, endQuoteChar=None, convertWhitespaceEscapes=True)

  Bases: `pyparsing.Token`

  Token for matching strings that are delimited by quoting characters.

  Defined with the following parameters:

  > - quoteChar - string of one or more characters defining the quote delimiting string

  > - escChar - character to escape quotes, typically backslash (default= `None`)

  > - escQuote - special quote sequence to escape an embedded quote string (such as SQL’s `""` to escape an embedded `"`) (default= `None`)

  > - multiline - boolean indicating whether quotes can span multiple lines (default= `False`)

  > - unquoteResults - boolean indicating whether the matched text should be unquoted (default= `True`)

  > - endQuoteChar - string of one or more characters defining the end of the quote delimited string (default= `None` => same as quoteChar)

  > - convertWhitespaceEscapes - convert escaped whitespace (`'\t'`, `'\n'`, etc.) to actual whitespace (default= `True`)

  Example:

      qs = QuotedString('"')
      print(qs.searchString('lsjdf "This is the quote" sldjf'))
      complex_qs = QuotedString('{{', endQuoteChar='}}')
      print(complex_qs.searchString('lsjdf {{This is the "quote"}} sldjf'))
      sql_qs = QuotedString('"', escQuote='""')
      print(sql_qs.searchString('lsjdf "This is the quote with ""embedded"" quotes" sldjf'))

  prints:

      [['This is the quote']]
      [['This is the "quote"']]
      [['This is the quote with "embedded" quotes']]

  parseImpl(instring, loc, doActions=True)

exception pyparsing.RecursiveGrammarException(parseElementList)

  Bases: `Exception`

  exception thrown by `ParserElement.validate` if the grammar could be improperly recursive

class pyparsing.Regex(pattern, flags=0, asGroupList=False, asMatch=False)

  Bases: `pyparsing.Token`

  Token for matching strings that match a given regular expression. Defined with string specifying the regular expression in a form recognized by the stdlib Python re module. If the given regex contains named groups (defined using `(?P<name>...)`), these will be preserved as named parse results.

  If instead of the Python stdlib re module you wish to use a different RE module (such as the regex module), you can replace it by either building your Regex object with a compiled RE that was compiled using regex:

  Example:

      realnum = Regex(r"[+-]?\d+\.\d*")
      date = Regex(r'(?P<year>\d{4})-(?P<month>\d\d?)-(?P<day>\d\d?)')
      # ref: https://stackoverflow.com/questions/267399/how-do-you-match-only-valid-roman-numerals-with-a-regular-expression
      roman = Regex(r"M{0,4}(CM|CD|D?{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})")

      # use regex module instead of stdlib re module to construct a Regex using
      # a compiled regular expression
      import regex
      parser = pp.Regex(regex.compile(r'[0-9]'))

  parseImpl(instring, loc, doActions=True)
  parseImplAsGroupList(instring, loc, doActions=True)
  parseImplAsMatch(instring, loc, doActions=True)
  sub(repl)

    Return Regex with an attached parse action to transform the parsed result as if called using re.sub(expr, repl, string).

    Example:

        make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2</\1>")
        print(make_html.transformString("h1:main title:"))
        # prints "<h1>main title</h1>"

class pyparsing.SkipTo(other, include=False, ignore=None, failOn=None)

  Bases: `pyparsing.ParseElementEnhance`

  Token for skipping over all undefined text until the matched expression is found.

  Parameters:

    - expr - target expression marking the end of the data to be skipped

    - include - (default= `False`) if True, the target expression is also parsed

        (the skipped text and target expression are returned as a 2-element list).

    - ignore - (default= `None`) used to define grammars (typically quoted strings and

        comments) that might contain false matches to the target expression

    - failOn - (default= `None`) define expressions that are not allowed to be

        included in the skipped test; if found before the target expression is found, the SkipTo is not a match

  Example:

      report = '''
          Outstanding Issues Report - 1 Jan 2000

             # | Severity | Description                               |  Days Open
          -----+----------+-------------------------------------------+-----------
           101 | Critical | Intermittent system crash                 |          6
            94 | Cosmetic | Spelling error on Login ('log|n')         |         14
            79 | Minor    | System slow when running too many reports |         47
          '''
      integer = Word(nums)
      SEP = Suppress('|')
      # use SkipTo to simply match everything up until the next SEP
      # - ignore quoted strings, so that a '|' character inside a quoted string does not match
      # - parse action will call token.strip() for each matched token, i.e., the description body
      string_data = SkipTo(SEP, ignore=quotedString)
      string_data.setParseAction(tokenMap(str.strip))
      ticket_expr = (integer("issue_num") + SEP
                    + string_data("sev") + SEP
                    + string_data("desc") + SEP
                    + integer("days_open"))

      for tkt in ticket_expr.searchString(report):
          print tkt.dump()

  prints:

      ['101', 'Critical', 'Intermittent system crash', '6']
      - days_open: 6
      - desc: Intermittent system crash
      - issue_num: 101
      - sev: Critical
      ['94', 'Cosmetic', "Spelling error on Login ('log|n')", '14']
      - days_open: 14
      - desc: Spelling error on Login ('log|n')
      - issue_num: 94
      - sev: Cosmetic
      ['79', 'Minor', 'System slow when running too many reports', '47']
      - days_open: 47
      - desc: System slow when running too many reports
      - issue_num: 79
      - sev: Minor

  parseImpl(instring, loc, doActions=True)

class pyparsing.StringEnd

  Bases: `pyparsing._PositionToken`

  Matches if current position is at the end of the parse string

  parseImpl(instring, loc, doActions=True)

class pyparsing.StringStart

  Bases: `pyparsing._PositionToken`

  Matches if current position is at the beginning of the parse string

  parseImpl(instring, loc, doActions=True)

class pyparsing.Suppress(expr, savelist=False)

  Bases: `pyparsing.TokenConverter`

  Converter for ignoring the results of a parsed expression.

  Example:

      source = "a, b, c,d"
      wd = Word(alphas)
      wd_list1 = wd + ZeroOrMore(',' + wd)
      print(wd_list1.parseString(source))

      # often, delimiters that are useful during parsing are just in the
      # way afterward - use Suppress to keep them out of the parsed output
      wd_list2 = wd + ZeroOrMore(Suppress(',') + wd)
      print(wd_list2.parseString(source))

  prints:

      ['a', ',', 'b', ',', 'c', ',', 'd']
      ['a', 'b', 'c', 'd']

  (See also `delimitedList`.)

  postParse(instring, loc, tokenlist)
  suppress()

    Suppresses the output of this `ParserElement`; useful to keep punctuation from cluttering up returned output.

class pyparsing.Token

  Bases: `pyparsing.ParserElement`

  Abstract `ParserElement` subclass, for defining atomic matching patterns.

class pyparsing.TokenConverter(expr, savelist=False)

  Bases: `pyparsing.ParseElementEnhance`

  Abstract subclass of `ParseExpression`, for converting parsed results.

class pyparsing.White(ws=' \t\r\n', min=1, max=0, exact=0)

  Bases: `pyparsing.Token`

  Special matching class for matching whitespace. Normally, whitespace is ignored by pyparsing grammars. This class is included when some whitespace structures are significant. Define with a string containing the whitespace characters to be matched; default is `" \t\r\n"`. Also takes optional `min`, `max`, and `exact` arguments, as defined for the `Word` class.

  parseImpl(instring, loc, doActions=True)
  whiteStrs = {'\t': '<TAB>', '\n': '<LF>', '\x0c': '<FF>', '\r': '<CR>', ' ': '<SP>', '\xa0': '<NBSP>', '\u1680': '<OGHAM_SPACE_MARK>', '\u180e': '<MONGOLIAN_VOWEL_SEPARATOR>', '\u2000': '<EN_QUAD>', '\u2001': '<EM_QUAD>', '\u2002': '<EN_SPACE>', '\u2003': '<EM_SPACE>', '\u2004': '<THREE-PER-EM_SPACE>', '\u2005': '<FOUR-PER-EM_SPACE>', '\u2006': '<SIX-PER-EM_SPACE>', '\u2007': '<FIGURE_SPACE>', '\u2008': '<PUNCTUATION_SPACE>', '\u2009': '<THIN_SPACE>', '\u200a': '<HAIR_SPACE>', '\u200b': '<ZERO_WIDTH_SPACE>', '\u202f': '<NNBSP>', '\u205f': '<MMSP>', '\u3000': '<IDEOGRAPHIC_SPACE>'}

class pyparsing.Word(initChars, bodyChars=None, min=1, max=0, exact=0, asKeyword=False, excludeChars=None)

  Bases: `pyparsing.Token`

  Token for matching words composed of allowed character sets. Defined with string containing all allowed initial characters, an optional string containing allowed body characters (if omitted, defaults to the initial character set), and an optional minimum, maximum, and/or exact length. The default value for `min` is 1 (a minimum value < 1 is not valid); the default values for `max` and `exact` are 0, meaning no maximum or exact length restriction. An optional `excludeChars` parameter can list characters that might be found in the input `bodyChars` string; useful to define a word of all printables except for one or two characters, for instance.

  `srange` is useful for defining custom character set strings for defining `Word` expressions, using range notation from regular expression character sets.

  A common mistake is to use `Word` to match a specific literal string, as in `Word("Address")`. Remember that `Word` uses the string argument to define sets of matchable characters. This expression would match “Add”, “AAA”, “dAred”, or any other word made up of the characters ‘A’, ‘d’, ‘r’, ‘e’, and ‘s’. To match an exact literal string, use `Literal` or `Keyword`.

  pyparsing includes helper strings for building Words:

  > - `alphas`

  > - `nums`

  > - `alphanums`

  > - `hexnums`

  > - `alphas8bit` (alphabetic characters in ASCII range 128-255 - accented, tilded, umlauted, etc.)

  > - `punc8bit` (non-alphabetic characters in ASCII range 128-255 - currency, symbols, superscripts, diacriticals, etc.)

  > - `printables` (any non-whitespace character)

  Example:

      # a word composed of digits
      integer = Word(nums) # equivalent to Word("0123456789") or Word(srange("0-9"))

      # a word with a leading capital, and zero or more lowercase
      capital_word = Word(alphas.upper(), alphas.lower())

      # hostnames are alphanumeric, with leading alpha, and '-'
      hostname = Word(alphas, alphanums + '-')

      # roman numeral (not a strict parser, accepts invalid mix of characters)
      roman = Word("IVXLCDM")

      # any string of non-whitespace characters, except for ','
      csv_value = Word(printables, excludeChars=",")

  parseImpl(instring, loc, doActions=True)

class pyparsing.WordEnd(wordChars='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~')

  Bases: `pyparsing._PositionToken`

  Matches if the current position is at the end of a Word, and is not followed by any character in a given set of `wordChars` (default= `printables`). To emulate the `` behavior of regular expressions, use `WordEnd(alphanums)`. `WordEnd` will also match at the end of the string being parsed, or at the end of a line.

  parseImpl(instring, loc, doActions=True)

class pyparsing.WordStart(wordChars='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~')

  Bases: `pyparsing._PositionToken`

  Matches if the current position is at the beginning of a Word, and is not preceded by any character in a given set of `wordChars` (default= `printables`). To emulate the `` behavior of regular expressions, use `WordStart(alphanums)`. `WordStart` will also match at the beginning of the string being parsed, or at the beginning of a line.

  parseImpl(instring, loc, doActions=True)

class pyparsing.ZeroOrMore(expr, stopOn=None)

  Bases: `pyparsing._MultipleMatch`

  Optional repetition of zero or more of the given expression.

  Parameters:

    - expr - expression that must match zero or more times

    - stopOn - (default= `None`) - expression for a terminating sentinel

        (only required if the sentinel would ordinarily match the repetition expression)

  Example: similar to `OneOrMore`

  parseImpl(instring, loc, doActions=True)

pyparsing.cStyleComment = C style comment

  Comment of the form `/* ... */`

pyparsing.col(loc, strg)

  Returns current column within a string, counting newlines as line separators. The first column is number 1.

  Note: the default parsing behavior is to expand tabs in the input string before starting the parsing process. See `ParserElement.parseString` for more information on parsing strings containing `<TAB>` s, and suggested methods to maintain a consistent view of the parsed string, the parse location, and line and column positions within the parsed string.

pyparsing.commaSeparatedList = commaSeparatedList

  (Deprecated) Predefined expression of 1 or more printable words or quoted strings, separated by commas.

  This expression is deprecated in favor of `pyparsing_common.comma_separated_list`.

pyparsing.conditionAsParseAction(fn, message=None, fatal=False)

pyparsing.countedArray(expr, intExpr=None)

  Helper to define a counted list of expressions.

  This helper defines a pattern of the form:

      integer expr expr expr...

  where the leading integer tells how many expr expressions follow. The matched tokens returns the array of expr tokens as a list - the leading count token is suppressed.

  If `intExpr` is specified, it should be a pyparsing expression that produces an integer value.

  Example:

      countedArray(Word(alphas)).parseString('2 ab cd ef')  # -> ['ab', 'cd']

      # in this parser, the leading integer value is given in binary,
      # '10' indicating that 2 values are in the array
      binaryConstant = Word('01').setParseAction(lambda t: int(t[0], 2))
      countedArray(Word(alphas), intExpr=binaryConstant).parseString('10 ab cd ef')  # -> ['ab', 'cd']

pyparsing.cppStyleComment = C++ style comment

  Comment of either form `cStyleComment` or `dblSlashComment`

pyparsing.dblSlashComment = // comment

  Comment of the form `// ... (to end of line)`

pyparsing.delimitedList(expr, delim=',', combine=False)

  Helper to define a delimited list of expressions - the delimiter defaults to ‘,’. By default, the list elements and delimiters can have intervening whitespace, and comments, but this can be overridden by passing `combine=True` in the constructor. If `combine` is set to `True`, the matching tokens are returned as a single token string, with the delimiters included; otherwise, the matching tokens are returned as a list of tokens, with the delimiters suppressed.

  Example:

      delimitedList(Word(alphas)).parseString("aa,bb,cc") # -> ['aa', 'bb', 'cc']
      delimitedList(Word(hexnums), delim=':', combine=True).parseString("AA:BB:CC:DD:EE") # -> ['AA:BB:CC:DD:EE']

pyparsing.dictOf(key, value)

  Helper to easily and clearly define a dictionary by specifying the respective patterns for the key and value. Takes care of defining the `Dict`, `ZeroOrMore`, and `Group` tokens in the proper order. The key pattern can include delimiting markers or punctuation, as long as they are suppressed, thereby leaving the significant key text. The value pattern can include named results, so that the `Dict` results can include named token fields.

  Example:

      text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
      attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
      print(OneOrMore(attr_expr).parseString(text).dump())

      attr_label = label
      attr_value = Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join)

      # similar to Dict, but simpler call format
      result = dictOf(attr_label, attr_value).parseString(text)
      print(result.dump())
      print(result['shape'])
      print(result.shape)  # object attribute access works too
      print(result.asDict())

  prints:

      [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
      - color: light blue
      - posn: upper left
      - shape: SQUARE
      - texture: burlap
      SQUARE
      SQUARE
      {'color': 'light blue', 'shape': 'SQUARE', 'posn': 'upper left', 'texture': 'burlap'}

pyparsing.downcaseTokens(s, l, t)

  (Deprecated) Helper parse action to convert tokens to lower case. Deprecated in favor of `pyparsing_common.downcaseTokens`

pyparsing.htmlComment = HTML comment

  Comment of the form `<!-- ... -->`

pyparsing.indentedBlock(blockStatementExpr, indentStack, indent=True)

  Helper method for defining space-delimited indentation blocks, such as those used to define block statements in Python source code.

  Parameters:

  > - blockStatementExpr - expression defining syntax of statement that is repeated within the indented block

  > - indentStack - list created by caller to manage indentation stack (multiple statementWithIndentedBlock expressions within a single grammar should share a common indentStack)

  > - indent - boolean indicating whether block must be indented beyond the current level; set to False for block of left-most statements (default= `True`)

  A valid block must contain at least one `blockStatement`.

  Example:

      data = '''
      def A(z):
        A1
        B = 100
        G = A2
        A2
        A3
      B
      def BB(a,b,c):
        BB1
        def BBA():
          bba1
          bba2
          bba3
      C
      D
      def spam(x,y):
           def eggs(z):
               pass
      '''

      indentStack = [1]
      stmt = Forward()

      identifier = Word(alphas, alphanums)
      funcDecl = ("def" + identifier + Group("(" + Optional(delimitedList(identifier)) + ")") + ":")
      func_body = indentedBlock(stmt, indentStack)
      funcDef = Group(funcDecl + func_body)

      rvalue = Forward()
      funcCall = Group(identifier + "(" + Optional(delimitedList(rvalue)) + ")")
      rvalue << (funcCall | identifier | Word(nums))
      assignment = Group(identifier + "=" + rvalue)
      stmt << (funcDef | assignment | identifier)

      module_body = OneOrMore(stmt)

      parseTree = module_body.parseString(data)
      parseTree.pprint()

  prints:

      [['def',
        'A',
        ['(', 'z', ')'],
        ':',
        [['A1'], [['B', '=', '100']], [['G', '=', 'A2']], ['A2'], ['A3']]],
       'B',
       ['def',
        'BB',
        ['(', 'a', 'b', 'c', ')'],
        ':',
        [['BB1'], [['def', 'BBA', ['(', ')'], ':', [['bba1'], ['bba2'], ['bba3']]]]]],
       'C',
       'D',
       ['def',
        'spam',
        ['(', 'x', 'y', ')'],
        ':',
        [[['def', 'eggs', ['(', 'z', ')'], ':', [['pass']]]]]]]

pyparsing.infixNotation(baseExpr, opList, lpar=Suppress:("("), rpar=Suppress:(")"))

  Helper method for constructing grammars of expressions made up of operators working in a precedence hierarchy. Operators may be unary or binary, left- or right-associative. Parse actions can also be attached to operator expressions. The generated parser will also recognize the use of parentheses to override operator precedences (see example below).

  Note: if you define a deep operator list, you may see performance issues when using infixNotation. See `ParserElement.enablePackrat` for a mechanism to potentially improve your parser performance.

  Parameters:

    - baseExpr - expression representing the most basic element for the nested

    - opList - list of tuples, one for each operator precedence level in the expression grammar; each tuple is of the form `(opExpr, numTerms, rightLeftAssoc, parseAction)`, where:

      - opExpr is the pyparsing expression for the operator; may also be a string, which will be converted to a Literal; if numTerms is 3, opExpr is a tuple of two expressions, for the two operators separating the 3 terms

      - numTerms is the number of terms for this operator (must be 1, 2, or 3)

      - rightLeftAssoc is the indicator whether the operator is right or left associative, using the pyparsing-defined constants `opAssoc.RIGHT` and `opAssoc.LEFT`.

      - parseAction is the parse action to be associated with expressions matching this operator expression (the parse action tuple member may be omitted); if the parse action is passed a tuple or list of functions, this is equivalent to calling `setParseAction(*fn)` (`ParserElement.setParseAction`)

    - lpar - expression for matching left-parentheses (default= `Suppress('(')`)

    - rpar - expression for matching right-parentheses (default= `Suppress(')')`)

  Example:

      # simple example of four-function arithmetic with ints and
      # variable names
      integer = pyparsing_common.signed_integer
      varname = pyparsing_common.identifier

      arith_expr = infixNotation(integer | varname,
          [
          ('-', 1, opAssoc.RIGHT),
          (oneOf('* /'), 2, opAssoc.LEFT),
          (oneOf('+ -'), 2, opAssoc.LEFT),
          ])

      arith_expr.runTests('''
          5+3*6
          (5+3)*6
          -2--11
          ''', fullDump=False)

  prints:

      5+3*6
      [[5, '+', [3, '*', 6]]]

      (5+3)*6
      [[[5, '+', 3], '*', 6]]

      -2--11
      [[['-', 2], '-', ['-', 11]]]

pyparsing.javaStyleComment = C++ style comment

  Same as `cppStyleComment`

pyparsing.line(loc, strg)

  Returns the line of text containing loc within a string, counting newlines as line separators.

pyparsing.lineno(loc, strg)

  Returns current line number within a string, counting newlines as line separators. The first line is number 1.

  Note - the default parsing behavior is to expand tabs in the input string before starting the parsing process. See `ParserElement.parseString` for more information on parsing strings containing `<TAB>` s, and suggested methods to maintain a consistent view of the parsed string, the parse location, and line and column positions within the parsed string.

pyparsing.locatedExpr(expr)

  Helper to decorate a returned token with its starting and ending locations in the input string.

  This helper adds the following results names:

  > - locn_start = location where matched expression begins

  > - locn_end = location where matched expression ends

  > - value = the actual parsed results

  Be careful if the input text contains `<TAB>` characters, you may want to call `ParserElement.parseWithTabs`

  Example:

      wd = Word(alphas)
      for match in locatedExpr(wd).searchString("ljsdf123lksdjjf123lkkjj1222"):
          print(match)

  prints:

      [[0, 'ljsdf', 5]]
      [[8, 'lksdjjf', 15]]
      [[18, 'lkkjj', 23]]

pyparsing.makeHTMLTags(tagStr)

  Helper to construct opening and closing tag expressions for HTML, given a tag name. Matches tags in either upper or lower case, attributes with namespaces and with quoted or unquoted values.

  Example:

      text = '<td>More info at the <a href="https://github.com/pyparsing/pyparsing/wiki">pyparsing</a> wiki page</td>'
      # makeHTMLTags returns pyparsing expressions for the opening and
      # closing tags as a 2-tuple
      a, a_end = makeHTMLTags("A")
      link_expr = a + SkipTo(a_end)("link_text") + a_end

      for link in link_expr.searchString(text):
          # attributes in the <A> tag (like "href" shown here) are
          # also accessible as named results
          print(link.link_text, '->', link.href)

  prints:

      pyparsing -> https://github.com/pyparsing/pyparsing/wiki

pyparsing.makeXMLTags(tagStr)

  Helper to construct opening and closing tag expressions for XML, given a tag name. Matches tags only in the given upper/lower case.

  Example: similar to `makeHTMLTags`

pyparsing.matchOnlyAtCol(n)

  Helper method for defining parse actions that require matching at a specific column in the input text.

pyparsing.matchPreviousExpr(expr)

  Helper to define an expression that is indirectly defined from the tokens matched in a previous expression, that is, it looks for a ‘repeat’ of a previous expression. For example:

      first = Word(nums)
      second = matchPreviousExpr(first)
      matchExpr = first + ":" + second

  will match `"1:1"`, but not `"1:2"`. Because this matches by expressions, will not match the leading `"1:1"` in `"1:10"`; the expressions are evaluated first, and then compared, so `"1"` is compared with `"10"`. Do not use with packrat parsing enabled.

pyparsing.matchPreviousLiteral(expr)

  Helper to define an expression that is indirectly defined from the tokens matched in a previous expression, that is, it looks for a ‘repeat’ of a previous expression. For example:

      first = Word(nums)
      second = matchPreviousLiteral(first)
      matchExpr = first + ":" + second

  will match `"1:1"`, but not `"1:2"`. Because this matches a previous literal, will also match the leading `"1:1"` in `"1:10"`. If this is not desired, use `matchPreviousExpr`. Do not use with packrat parsing enabled.

pyparsing.nestedExpr(opener='(', closer=')', content=None, ignoreExpr=quotedString using single or double quotes)

  Helper method for defining nested lists enclosed in opening and closing delimiters (“(” and “)” are the default).

  Parameters:

    - opener - opening character for a nested list (default= `"("`); can also be a pyparsing expression

    - closer - closing character for a nested list (default= `")"`); can also be a pyparsing expression

    - content - expression for items within the nested lists (default= `None`)

    - ignoreExpr - expression for ignoring opening and closing delimiters (default= `quotedString`)

  If an expression is not provided for the content argument, the nested expression will capture all whitespace-delimited content between delimiters as a list of separate values.

  Use the `ignoreExpr` argument to define expressions that may contain opening or closing characters that should not be treated as opening or closing characters for nesting, such as quotedString or a comment expression. Specify multiple expressions using an `Or` or `MatchFirst`. The default is `quotedString`, but if no expressions are to be ignored, then pass `None` for this argument.

  Example:

      data_type = oneOf("void int short long char float double")
      decl_data_type = Combine(data_type + Optional(Word('*')))
      ident = Word(alphas+'_', alphanums+'_')
      number = pyparsing_common.number
      arg = Group(decl_data_type + ident)
      LPAR, RPAR = map(Suppress, "()")

      code_body = nestedExpr('{', '}', ignoreExpr=(quotedString | cStyleComment))

      c_function = (decl_data_type("type")
                    + ident("name")
                    + LPAR + Optional(delimitedList(arg), [])("args") + RPAR
                    + code_body("body"))
      c_function.ignore(cStyleComment)

      source_code = '''
          int is_odd(int x) {
              return (x%2);
          }

          int dec_to_hex(char hchar) {
              if (hchar >= '0' && hchar <= '9') {
                  return (ord(hchar)-ord('0'));
              } else {
                  return (10+ord(hchar)-ord('A'));
              }
          }
      '''
      for func in c_function.searchString(source_code):
          print("%(name)s (%(type)s) args: %(args)s" % func)

  prints:

      is_odd (int) args: [['int', 'x']]
      dec_to_hex (int) args: [['char', 'hchar']]

pyparsing.nullDebugAction(*args)

  ‘Do-nothing’ debug action, to suppress debugging output during parsing.

pyparsing.oneOf(strs, caseless=False, useRegex=True, asKeyword=False)

  Helper to quickly define a set of alternative Literals, and makes sure to do longest-first testing when there is a conflict, regardless of the input order, but returns a `MatchFirst` for best performance.

  Parameters:

  > - strs - a string of space-delimited literals, or a collection of string literals

  > - caseless - (default= `False`) - treat all literals as caseless

  > - useRegex - (default= `True`) - as an optimization, will generate a Regex object; otherwise, will generate a `MatchFirst` object (if `caseless=True` or `asKeyword=True`, or if creating a `Regex` raises an exception)

  > - asKeyword - (default=``False``) - enforce Keyword-style matching on the generated expressions

  Example:

      comp_oper = oneOf("< = > <= >= !=")
      var = Word(alphas)
      number = Word(nums)
      term = var | number
      comparison_expr = term + comp_oper + term
      print(comparison_expr.searchString("B = 12  AA=23 B<=AA AA>12"))

  prints:

      [['B', '=', '12'], ['AA', '=', '23'], ['B', '<=', 'AA'], ['AA', '>', '12']]

pyparsing.operatorPrecedence(baseExpr, opList, lpar=Suppress:("("), rpar=Suppress:(")"))

  (Deprecated) Former name of `infixNotation`, will be dropped in a future release.

pyparsing.originalTextFor(expr, asString=True)

  Helper to return the original, untokenized text for a given expression. Useful to restore the parsed fields of an HTML start tag into the raw tag text itself, or to revert separate tokens with intervening whitespace back to the original matching input text. By default, returns astring containing the original parsed text.

  If the optional `asString` argument is passed as `False`, then the return value is a `ParseResults` containing any results names that were originally matched, and a single token containing the original matched text from the input string. So if the expression passed to `originalTextFor` contains expressions with defined results names, you must set `asString` to `False` if you want to preserve those results name values.

  Example:

      src = "this is test <b> bold <i>text</i> </b> normal text "
      for tag in ("b", "i"):
          opener, closer = makeHTMLTags(tag)
          patt = originalTextFor(opener + SkipTo(closer) + closer)
          print(patt.searchString(src)[0])

  prints:

      ['<b> bold <i>text</i> </b>']
      ['<i>text</i>']

class pyparsing.pyparsing_common

  Bases: `object`

  Here are some common low-level expressions that may be useful in jump-starting parser development:

  > - numeric forms (`integers`, `reals`, `scientific notation`)

  > - common `programming identifiers`

  > - network addresses (`MAC`, `IPv4`, `IPv6`)

  > - ISO8601 `dates` and `datetime`

  > - `UUID`

  > - `comma-separated list`

  Parse actions:

  > - `convertToInteger`

  > - `convertToFloat`

  > - `convertToDate`

  > - `convertToDatetime`

  > - `stripHTMLTags`

  > - `upcaseTokens`

  > - `downcaseTokens`

  Example:

      pyparsing_common.number.runTests('''
          # any int or real number, returned as the appropriate type
          100
          -100
          +100
          3.14159
          6.02e23
          1e-12
          ''')

      pyparsing_common.fnumber.runTests('''
          # any int or real number, returned as float
          100
          -100
          +100
          3.14159
          6.02e23
          1e-12
          ''')

      pyparsing_common.hex_integer.runTests('''
          # hex numbers
          100
          FF
          ''')

      pyparsing_common.fraction.runTests('''
          # fractions
          1/2
          -3/4
          ''')

      pyparsing_common.mixed_integer.runTests('''
          # mixed fractions
          1
          1/2
          -3/4
          1-3/4
          ''')

      import uuid
      pyparsing_common.uuid.setParseAction(tokenMap(uuid.UUID))
      pyparsing_common.uuid.runTests('''
          # uuid
          12345678-1234-5678-1234-567812345678
          ''')

  prints:

      # any int or real number, returned as the appropriate type
      100
      [100]

      -100
      [-100]

      +100
      [100]

      3.14159
      [3.14159]

      6.02e23
      [6.02e+23]

      1e-12
      [1e-12]

      # any int or real number, returned as float
      100
      [100.0]

      -100
      [-100.0]

      +100
      [100.0]

      3.14159
      [3.14159]

      6.02e23
      [6.02e+23]

      1e-12
      [1e-12]

      # hex numbers
      100
      [256]

      FF
      [255]

      # fractions
      1/2
      [0.5]

      -3/4
      [-0.75]

      # mixed fractions
      1
      [1]

      1/2
      [0.5]

      -3/4
      [-0.75]

      1-3/4
      [1.75]

      # uuid
      12345678-1234-5678-1234-567812345678
      [UUID('12345678-1234-5678-1234-567812345678')]

  comma_separated_list = comma separated list

    Predefined expression of 1 or more printable words or quoted strings, separated by commas.

  static convertToDate(fmt='%Y-%m-%d')

    Helper to create a parse action for converting parsed date string to Python datetime.date

    Params -

      - fmt - format to be passed to datetime.strptime (default= `"%Y-%m-%d"`)

    Example:

        date_expr = pyparsing_common.iso8601_date.copy()
        date_expr.setParseAction(pyparsing_common.convertToDate())
        print(date_expr.parseString("1999-12-31"))

    prints:

        [datetime.date(1999, 12, 31)]

  static convertToDatetime(fmt='%Y-%m-%dT%H:%M:%S.%f')

    Helper to create a parse action for converting parsed datetime string to Python datetime.datetime

    Params -

      - fmt - format to be passed to datetime.strptime (default= `"%Y-%m-%dT%H:%M:%S.%f"`)

    Example:

        dt_expr = pyparsing_common.iso8601_datetime.copy()
        dt_expr.setParseAction(pyparsing_common.convertToDatetime())
        print(dt_expr.parseString("1999-12-31T23:59:59.999"))

    prints:

        [datetime.datetime(1999, 12, 31, 23, 59, 59, 999000)]

  convertToFloat(l, t)

    Parse action for converting parsed numbers to Python float

  convertToInteger(l, t)

    Parse action for converting parsed integers to Python int

  static downcaseTokens(s, l, t)

    Parse action to convert tokens to lower case.

  fnumber = fnumber

    any int or real number, returned as float

  fraction = fraction

    fractional expression of an integer divided by an integer, returns a float

  hex_integer = hex integer

    expression that parses a hexadecimal integer, returns an int

  identifier = identifier

    typical code identifier (leading alpha or ‘_’, followed by 0 or more alphas, nums, or ‘_’)

  integer = integer

    expression that parses an unsigned integer, returns an int

  ipv4_address = IPv4 address

    IPv4 address (`0.0.0.0 - 255.255.255.255`)

  ipv6_address = IPv6 address

    IPv6 address (long, short, or mixed form)

  iso8601_date = ISO8601 date

    ISO8601 date (`yyyy-mm-dd`)

  iso8601_datetime = ISO8601 datetime

    ISO8601 datetime (`yyyy-mm-ddThh:mm:ss.s(Z|+-00:00)`) - trailing seconds, milliseconds, and timezone optional; accepts separating `'T'` or `' '`

  mac_address = MAC address

    MAC address xx:xx:xx:xx:xx (may also have ‘-’ or ‘.’ delimiters)

  mixed_integer = fraction or mixed integer-fraction

    mixed integer of the form ‘integer - fraction’, with optional leading integer, returns float

  number = {real number with scientific notation | real number | signed integer}

    any numeric expression, returns the corresponding Python type

  real = real number

    expression that parses a floating point number and returns a float

  sci_real = real number with scientific notation

    expression that parses a floating point number with optional scientific notation and returns a float

  signed_integer = signed integer

    expression that parses an integer with optional leading sign, returns an int

  static stripHTMLTags(s, l, tokens)

    Parse action to remove HTML tags from web page HTML source

    Example:

        # strip HTML links from normal text
        text = '<td>More info at the <a href="https://github.com/pyparsing/pyparsing/wiki">pyparsing</a> wiki page</td>'
        td, td_end = makeHTMLTags("TD")
        table_text = td + SkipTo(td_end).setParseAction(pyparsing_common.stripHTMLTags)("body") + td_end
        print(table_text.parseString(text).body)

    Prints:

        More info at the pyparsing wiki page

  static upcaseTokens(s, l, t)

    Parse action to convert tokens to upper case.

  uuid = UUID

    UUID (`xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`)

class pyparsing.pyparsing_unicode

  Bases: `pyparsing.unicode_set`

  A namespace class for defining common language unicode_sets.

  class Arabic

    Bases: `pyparsing.unicode_set`

    Unicode set for Arabic Unicode Character Range

  class CJK

    Bases: `pyparsing.pyparsing_unicode.Chinese`, `pyparsing.pyparsing_unicode.Japanese`, `pyparsing.pyparsing_unicode.Korean`

    Unicode set for combined Chinese, Japanese, and Korean (CJK) Unicode Character Range

  class Chinese

    Bases: `pyparsing.unicode_set`

    Unicode set for Chinese Unicode Character Range

  class Cyrillic

    Bases: `pyparsing.unicode_set`

    Unicode set for Cyrillic Unicode Character Range

  class Devanagari

    Bases: `pyparsing.unicode_set`

    Unicode set for Devanagari Unicode Character Range

  class Greek

    Bases: `pyparsing.unicode_set`

    Unicode set for Greek Unicode Character Ranges

  class Hebrew

    Bases: `pyparsing.unicode_set`

    Unicode set for Hebrew Unicode Character Range

  class Japanese

    Bases: `pyparsing.unicode_set`

    Unicode set for Japanese Unicode Character Range, combining Kanji, Hiragana, and Katakana ranges

    class Hiragana

      Bases: `pyparsing.unicode_set`

      Unicode set for Hiragana Unicode Character Range

    class Kanji

      Bases: `pyparsing.unicode_set`

      Unicode set for Kanji Unicode Character Range

    class Katakana

      Bases: `pyparsing.unicode_set`

      Unicode set for Katakana Unicode Character Range

    ひらがな

      alias of `pyparsing.pyparsing_unicode.Japanese.Hiragana`

    カタカナ

      alias of `pyparsing.pyparsing_unicode.Japanese.Katakana`

    漢字

      alias of `pyparsing.pyparsing_unicode.Japanese.Kanji`

  class Korean

    Bases: `pyparsing.unicode_set`

    Unicode set for Korean Unicode Character Range

  class Latin1

    Bases: `pyparsing.unicode_set`

    Unicode set for Latin-1 Unicode Character Range

  class LatinA

    Bases: `pyparsing.unicode_set`

    Unicode set for Latin-A Unicode Character Range

  class LatinB

    Bases: `pyparsing.unicode_set`

    Unicode set for Latin-B Unicode Character Range

  class Thai

    Bases: `pyparsing.unicode_set`

    Unicode set for Thai Unicode Character Range

  Ελληνικά

    alias of `pyparsing.pyparsing_unicode.Greek`

  кириллица

    alias of `pyparsing.pyparsing_unicode.Cyrillic`

  العربية

    alias of `pyparsing.pyparsing_unicode.Arabic`

  ไทย

    alias of `pyparsing.pyparsing_unicode.Thai`

  中文

    alias of `pyparsing.pyparsing_unicode.Chinese`

  日本語

    alias of `pyparsing.pyparsing_unicode.Japanese`

  한국어

    alias of `pyparsing.pyparsing_unicode.Korean`

pyparsing.pythonStyleComment = Python style comment

  Comment of the form `# ... (to end of line)`

pyparsing.removeQuotes(s, l, t)

  Helper parse action for removing quotation marks from parsed quoted strings.

  Example:

      # by default, quotation marks are included in parsed results
      quotedString.parseString("'Now is the Winter of our Discontent'") # -> ["'Now is the Winter of our Discontent'"]

      # use removeQuotes to strip quotation marks from parsed results
      quotedString.setParseAction(removeQuotes)
      quotedString.parseString("'Now is the Winter of our Discontent'") # -> ["Now is the Winter of our Discontent"]

pyparsing.replaceHTMLEntity(t)

  Helper parser action to replace common HTML entities with their special characters

pyparsing.replaceWith(replStr)

  Helper method for common parse actions that simply return a literal value. Especially useful when used with `transformString` ().

  Example:

      num = Word(nums).setParseAction(lambda toks: int(toks[0]))
      na = oneOf("N/A NA").setParseAction(replaceWith(math.nan))
      term = na | num

      OneOrMore(term).parseString("324 234 N/A 234") # -> [324, 234, nan, 234]

pyparsing.srange(s)

  Helper to easily define string ranges for use in Word construction. Borrows syntax from regexp ‘[]’ string range definitions:

      srange("[0-9]")   -> "0123456789"
      srange("[a-z]")   -> "abcdefghijklmnopqrstuvwxyz"
      srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_"

  The input string must be enclosed in []’s, and the returned string is the expanded character set joined into a single string. The values enclosed in the []’s may be:

  > - a single character

  > - an escaped character with a leading backslash (such as `\-` or `\]`)

  > - an escaped hex character with a leading `'\x'` (`\x21`, which is a `'!'` character) (`\0x##` is also supported for backwards compatibility)

  > - an escaped octal character with a leading `'\0'` (`\041`, which is a `'!'` character)

  > - a range of any of the above, separated by a dash (`'a-z'`, etc.)

  > - any combination of the above (`'aeiouy'`, `'a-zA-Z0-9_$'`, etc.)

pyparsing.tokenMap(func, *args)

  Helper to define a parse action by mapping a function to all elements of a ParseResults list. If any additional args are passed, they are forwarded to the given function as additional arguments after the token, as in `hex_integer = Word(hexnums).setParseAction(tokenMap(int, 16))`, which will convert the parsed data to an integer using base 16.

  Example (compare the last to example in `ParserElement.transformString`:

      hex_ints = OneOrMore(Word(hexnums)).setParseAction(tokenMap(int, 16))
      hex_ints.runTests('''
          00 11 22 aa FF 0a 0d 1a
          ''')

      upperword = Word(alphas).setParseAction(tokenMap(str.upper))
      OneOrMore(upperword).runTests('''
          my kingdom for a horse
          ''')

      wd = Word(alphas).setParseAction(tokenMap(str.title))
      OneOrMore(wd).setParseAction(' '.join).runTests('''
          now is the winter of our discontent made glorious summer by this sun of york
          ''')

  prints:

      00 11 22 aa FF 0a 0d 1a
      [0, 17, 34, 170, 255, 10, 13, 26]

      my kingdom for a horse
      ['MY', 'KINGDOM', 'FOR', 'A', 'HORSE']

      now is the winter of our discontent made glorious summer by this sun of york
      ['Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York']

pyparsing.traceParseAction(f)

  Decorator for debugging parse actions.

  When the parse action is called, this decorator will print `">> entering method-name(line:<current_source_line>, <parse_location>, <matched_tokens>)"`. When the parse action completes, the decorator will print `"<<"` followed by the returned value, or any exception that the parse action raised.

  Example:

      wd = Word(alphas)

      @traceParseAction
      def remove_duplicate_chars(tokens):
          return ''.join(sorted(set(''.join(tokens))))

      wds = OneOrMore(wd).setParseAction(remove_duplicate_chars)
      print(wds.parseString("slkdjs sld sldd sdlf sdljf"))

  prints:

      >>entering remove_duplicate_chars(line: 'slkdjs sld sldd sdlf sdljf', 0, (['slkdjs', 'sld', 'sldd', 'sdlf', 'sdljf'], {}))
      <<leaving remove_duplicate_chars (ret: 'dfjkls')
      ['dfjkls']

pyparsing.ungroup(expr)

  Helper to undo pyparsing’s default grouping of And expressions, even if all but one are non-empty.

class pyparsing.unicode_set

  Bases: `object`

  A set of Unicode characters, for language-specific strings for `alphas`, `nums`, `alphanums`, and `printables`. A unicode_set is defined by a list of ranges in the Unicode character set, in a class attribute `_ranges`, such as:

      _ranges = [(0x0020, 0x007e), (0x00a0, 0x00ff),]

  A unicode set can also be defined using multiple inheritance of other unicode sets:

      class CJK(Chinese, Japanese, Korean):
          pass

  alphanums = ''
  alphas = ''
  nums = ''
  printables = ''

pyparsing.upcaseTokens(s, l, t)

  (Deprecated) Helper parse action to convert tokens to upper case. Deprecated in favor of `pyparsing_common.upcaseTokens`

pyparsing.withAttribute(*args, **attrDict)

  Helper to create a validating parse action to be used with start tags created with `makeXMLTags` or `makeHTMLTags`. Use `withAttribute` to qualify a starting tag with a required attribute value, to avoid false matches on common tags such as `<TD>` or `<DIV>`.

  Call `withAttribute` with a series of attribute names and values. Specify the list of filter attributes names and values as:

  > - keyword arguments, as in `(align="right")`, or

  > - as an explicit dict with `**` operator, when an attribute name is also a Python reserved word, as in `**{"class":"Customer", "align":"right"}`

  > - a list of name-value tuples, as in `(("ns1:class", "Customer"), ("ns2:align", "right"))`

  For attribute names with a namespace prefix, you must use the second form. Attribute names are matched insensitive to upper/lower case.

  If just testing for `class` (with or without a namespace), use `withClass`.

  To verify that the attribute exists, but without specifying a value, pass `withAttribute.ANY_VALUE` as the value.

  Example:

      html = '''
          <div>
          Some text
          <div type="grid">1 4 0 1 0</div>
          <div type="graph">1,3 2,3 1,1</div>
          <div>this has no type</div>
          </div>

      '''
      div,div_end = makeHTMLTags("div")

      # only match div tag having a type attribute with value "grid"
      div_grid = div().setParseAction(withAttribute(type="grid"))
      grid_expr = div_grid + SkipTo(div | div_end)("body")
      for grid_header in grid_expr.searchString(html):
          print(grid_header.body)

      # construct a match with any div tag having a type attribute, regardless of the value
      div_any_type = div().setParseAction(withAttribute(type=withAttribute.ANY_VALUE))
      div_expr = div_any_type + SkipTo(div | div_end)("body")
      for div_header in div_expr.searchString(html):
          print(div_header.body)

  prints:

      1 4 0 1 0

      1 4 0 1 0
      1,3 2,3 1,1

pyparsing.withClass(classname, namespace='')

  Simplified version of `withAttribute` when matching on a div class - made difficult because `class` is a reserved word in Python.

  Example:

      html = '''
          <div>
          Some text
          <div class="grid">1 4 0 1 0</div>
          <div class="graph">1,3 2,3 1,1</div>
          <div>this &lt;div&gt; has no class</div>
          </div>

      '''
      div,div_end = makeHTMLTags("div")
      div_grid = div().setParseAction(withClass("grid"))

      grid_expr = div_grid + SkipTo(div | div_end)("body")
      for grid_header in grid_expr.searchString(html):
          print(grid_header.body)

      div_any_type = div().setParseAction(withClass(withAttribute.ANY_VALUE))
      div_expr = div_any_type + SkipTo(div | div_end)("body")
      for div_header in div_expr.searchString(html):
          print(div_header.body)

  prints:

      1 4 0 1 0

      1 4 0 1 0
      1,3 2,3 1,1