官方https://docs.python.org/3.4/library/string.html#string.Formatter

6.1. string — Common string operations

Source code: Lib/string.py

See also

Text Sequence Type — str

String Methods

6.1.1. String constants

The constants defined in this module are:

string.ascii_letters

The concatenation of the ascii_lowercase and ascii_uppercase constants described below. This value is not locale-dependent.

string.ascii_lowercase

The lowercase letters ‘abcdefghijklmnopqrstuvwxyz‘. This value is not locale-dependent and will not change.

string.ascii_uppercase

The uppercase letters ‘ABCDEFGHIJKLMNOPQRSTUVWXYZ‘. This value is not locale-dependent and will not change.

string.digits

The string ‘0123456789‘.

string.hexdigits

The string ‘0123456789abcdefABCDEF‘.

string.octdigits

The string ‘01234567‘.

string.punctuation

String of ASCII characters which are considered punctuation characters in the C locale.

string.printable

String of ASCII characters which are considered printable. This is a combination of digits, ascii_letters, punctuation, and whitespace.

string.whitespace

A string containing all ASCII characters that are considered whitespace. This includes the characters space, tab, linefeed, return, formfeed, and vertical tab.