s.capitalize()

make the first character have upper case and the rest lower case.

s.center(width, fillchar=None)

Padding is done using the specified fill character (default is a space).

s.count(sub, start=None, end=None)

从一个范围内统计某str出现的次数

s.encode(encoding='UTF-8', errors='strict') 

encode() 方法以指定的编码格式编码字符串，默认编码为 'utf-8'。将字符串由string类型变成bytes类型

s.endswith(suffix, start=None, end=None)

Return True is s ends with the specified suffix, False otherwise.

s.expandtabs(tabsize=8)

将字符串中包含的\t 转换成tabsize个空格

s.find(sub, start=None, end=None)

s.index(sub, start=None, end=None)

Like s.find() but raise ValueError when the substring is not found

s.isalnum()

至少一个字符，且都是字母或数字才返回True

s.isalpha()

至少一个字符，且都是字母才返回True

s.isdecimal()

Return True if there are only decimal characters is S

s.isdigit()

s.isidentifier()

字符串为关键字返回true