# stdnum.issn

ISSN (International Standard Serial Number).

The ISSN (International Standard Serial Number) is the standard code to identify periodical publications (e.g. magazines).

An ISSN has 8 digits and is formatted in two pairs of 4 digits separated by a hyphen. The last digit is a check digit and may be 0-9 or X (similar to ISBN-10).

More information:

- https://en.wikipedia.org/wiki/International_Standard_Serial_Number

- https://www.issn.org/

    >>> validate('0024-9319')
    '00249319'
    >>> validate('0032147X')
    Traceback (most recent call last):
        ...
    InvalidChecksum: ...
    >>> validate('003214712')
    Traceback (most recent call last):
        ...
    InvalidLength: ...
    >>> compact('0032-1478')
    '00321478'
    >>> format('00249319')
    '0024-9319'
    >>> to_ean('0264-3596')
    '9770264359008'

stdnum.issn.calc_check_digit(number)

  Calculate the ISSN check digit for 8-digit numbers. The number passed should not have the check digit included.

stdnum.issn.compact(number)

  Convert the ISSN to the minimal representation. This strips the number of any valid ISSN separators and removes surrounding whitespace.

stdnum.issn.format(number)

  Reformat the number to the standard presentation format.

stdnum.issn.is_valid(number)

  Check if the number provided is a valid ISSN.

stdnum.issn.to_ean(number, issue_code='00')

  Convert the number to EAN-13 format.

stdnum.issn.validate(number)

  Check if the number is a valid ISSN. This checks the length and whether the check digit is correct.