diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst index 8b896011734df5..1b64f30a518744 100644 --- a/Doc/library/stdtypes.rst +++ b/Doc/library/stdtypes.rst @@ -1841,7 +1841,16 @@ expression support in the :mod:`re` module). intended to remove all case distinctions in a string. For example, the German lowercase letter ``'ß'`` is equivalent to ``"ss"``. Since it is already lowercase, :meth:`lower` would do nothing to ``'ß'``; :meth:`casefold` - converts it to ``"ss"``. + converts it to ``"ss"``. This is useful for case-insensitive string comparisons. + For example: + + .. doctest:: + + >>> 'straße'.lower() == 'strasse' + False + >>> 'straße'.casefold() == 'strasse' + True + The casefolding algorithm is `described in section 3.13.3 'Default Case Folding' of the Unicode Standard @@ -2250,7 +2259,12 @@ expression support in the :mod:`re` module). .. method:: str.lower() Return a copy of the string with all the cased characters [4]_ converted to - lowercase. + lowercase. For example: + + .. doctest:: + + >>> 'Lower Method Example'.lower() + 'lower method example' The lowercasing algorithm used is `described in section 3.13.2 'Default Case Conversion' of the Unicode Standard