String.casefold and String.Lower differences in Python

string.casefold和 string.lower DifferencePython 3.3 introduces a string.casefold method whose effect is very similar to that of turning a string.lower string into lowercase, so what's the difference between them? Their respective application scenarios? when Unicode is used casefold string.casefold Official Note:

Casefolding is similar to lowercasing and more aggressive because it's intended to remove all case distinctions in a stri Ng. For example, the German lowercase are ‘ß‘ equivalent to "ss" . Since It is already lowercase, lower() would does nothing to ‘ß‘ ; casefold() Converts it to "ss" .

The casefolding algorithm is described in sections 3.13 of the Unicode standard

lower()‘A-Z‘It is only valid for ASCII, but in some other languages there is no way to get a lowercase case. The example in the document is the lowercase in German ‘ß‘ ‘ss‘ :

s = ‘ß‘s.lower() #  ‘ß‘s.casefold() # ‘ss‘

string.lower Official Note:

Return a copy of the string with all the cased characters [4] converted to lowercase.

The lowercasing algorithm used is described in sections 3.13 of the Unicode standard

Reference

Https://docs.python.org/3/library/stdtypes.html#str.casefold

https://segmentfault.com/q/1010000004586740/a-1020000004586838

Summary

Chinese & English Environment under, continue to use lower() no problem; To work with other languages and when case is presentcasefold()

String.casefold and String.Lower differences in Python