Python-string类学习

今天在练习一个字符串操作时，需要把大小写字母全部都保存到一个列表中。联想到shell中都有使用POSIX字符类，如[:alnum:]表示字母与数字字符，[:alpha:]表示字母字符， [:digit:]表示数字字符，python作为高级、流行的编程语言，理论上应该有提供类似功能的模块。

仔细查了下，发现string模块刚好符合我需要的功能，该模块包括了以下常量字符集。

The constants defined in this module are:string.ascii_lettersThe concatenation of the ascii_lowercase and ascii_uppercase constants described below. This value is not locale-dependent.string.ascii_lowercaseThe lowercase letters 'abcdefghijklmnopqrstuvwxyz'. This value is not locale-dependent and will not change.string.ascii_uppercaseThe uppercase letters 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'. This value is not locale-dependent and will not change.string.digitsThe string '0123456789'.string.hexdigitsThe string '0123456789abcdefABCDEF'.string.octdigitsThe string '01234567'.string.punctuationString of ASCII characters which are considered punctuation characters in the C locale.string.printableString of ASCII characters which are considered printable. This is a combination of digits, ascii_letters, punctuation, and whitespace.string.whitespaceA string containing all ASCII characters that are considered whitespace. This includes the characters space, tab, linefeed, return, formfeed, and vertical tab.

这些常量把常用的一些字符集都列举出来了，我们可以根据自己的需要进行选择。

另外，string模块还有一个capwords函数，即把传入的字符串变成首字母大写。

 string.capwords("abc,abc,test", sep=",")
'Abc,Abc,Test'