Skip to main content
`Ctrl`+`K`

# pandas.Series.map

Series.map(arg, na_action=None)

  Map values of Series according to an input mapping or function.

  Used for substituting each value in a Series with another value, that may be derived from a function, a `dict` or a `Series`.

  Parameters:
    arg function, collections.abc.Mapping subclass or Series

      Mapping correspondence.

    na_action{None, ‘ignore’}, default None

      If ‘ignore’, propagate NaN values, without passing them to the mapping correspondence.

  Returns:
    Series

      Same index as caller.

  See also

  `Series.apply`

    For applying more complex functions on a Series.

  `Series.replace`

    Replace values given in to_replace with value.

  `DataFrame.apply`

    Apply a function row-/column-wise.

  `DataFrame.map`

    Apply a function elementwise on a whole DataFrame.

  Notes

  When `arg` is a dictionary, values in Series that are not in the dictionary (as keys) are converted to `NaN`. However, if the dictionary is a `dict` subclass that defines `__missing__` (i.e. provides a method for default values), then this default is used rather than `NaN`.

  Examples

      >>> s = pd.Series(['cat', 'dog', np.nan, 'rabbit'])
      >>> s
      0      cat
      1      dog
      2      NaN
      3   rabbit
      dtype: object

  `map` accepts a `dict` or a `Series`. Values that are not found in the `dict` are converted to `NaN`, unless the dict has a default value (e.g. `defaultdict`):

      >>> s.map({'cat': 'kitten', 'dog': 'puppy'})
      0   kitten
      1    puppy
      2      NaN
      3      NaN
      dtype: object

  It also accepts a function:

      >>> s.map('I am a {}'.format)
      0       I am a cat
      1       I am a dog
      2       I am a nan
      3    I am a rabbit
      dtype: object

  To avoid applying the function to missing values (and keep them as `NaN`) `na_action='ignore'` can be used:

      >>> s.map('I am a {}'.format, na_action='ignore')
      0     I am a cat
      1     I am a dog
      2            NaN
      3  I am a rabbit
      dtype: object