字符串的操作

capitalize 首字母大写

>>> like = 'super beauty'
>>> like.capitalize()
'Super beauty'

count  返回指定字符串的个数

>>> like = 'super beauty'
>>> like.count('u')
2

center 返回指定长度的字符串，中间是旧的字符串，两边用指定字符串补充

>>> like = 'super beauty'
>>> like.center(30, '-')
'---------super beauty---------'

endswith 判断是否以指定字符串结尾

>>> like = 'super beauty'
>>> like.endswith('ty')
True

expandtabs 制表符替换为指定个数的空格

>>> like = 'super	beauty'
>>> like.expandtabs(tabsize=20)
'super               beauty'

find 返回指定字符串在字符串中的索引（同index?）

>>> like = 'super beauty'
>>> like.find('u')
1

format 很常用，不多说

>>> like = 'super beauty'
>>> print('I like {like}'.format(like=like))
I like super beauty

format_map 与format的却别是参数类型不同，这个是字典

>>> like = 'super beauty'
>>> print('I like {like}'.format_map({'like': like}))
I like super beauty

isalnum 字符串是否由数字和字母组成

>>> like = '1 super beauty'
>>> like.isalnum()
False
>>> like = '1superbeauty'
>>> like.isalnum()
True

isdecimal 字符串是否只包含十进制字符(Python3)

>>> '2'.isdecimal()
True
>>> '2.23'.isdecimal()
False

isdigit 字符串是否只由数字组成

>>> '3.14'.isdigit()
False
>>> '314'.isdigit()
True
>>>

isidentifier  字符串是否为合法的标识符（是否可用作变量名）

>>> '_2a'.isidentifier()
True
>>> '2a'.isidentifier()
False

islower 字符串是否为小写

>>> 'fb_3434'.islower()
True
>>> 'fB_3434'.islower()
False

ismumeric  同isdigit

isspace 字符串是否只由空格组成

>>> ' '.isspace()
True
>>> ' f'.isspace()
False

istitle 个单词的首字母是否大写

>>> 'I like beauty'.istitle()
False
>>> 'I Like Beauty'.istitle()
True

isprintable 是否可以打印（只有linux的设备终端驱动程序文件才不能打印）

isupper 是否大写

>>> 'I Like Beauty'.isupper()
False
>>> 'I LIKE BEAUTY'.isupper()
True

join 连接字符串

>>> like = ['I', 'like', 'beauty']
>>> ' '.join(like)
'I like beauty'

ljust 类似于center，但这个把指定字符串放到左边而不是中间

>>> say = 'I like beauty'
>>> say.ljust(20, '!')
'I like beauty!!!!!!!'

rjust 同理

lower upper 小写/大写

>>> say = 'I like beauty'
>>> say.lower()
'i like beauty'
>>> say.upper()
'I LIKE BEAUTY'

lstrip 去掉字符串左边的空格和回车

>>> say = ' I like beauty'
>>> say.lstrip()
'I like beauty'

rstrip 同理

maketrans 字符转换

>>> say = 'I like beauty'
>>> t = str.maketrans('ie', '12')
>>> say.translate(t)
'I l1k2 b2auty'

replace 替换（第三个参数为替换的个数，默认替换所有匹配的）

>>> say = 'I like beauty'
>>> say.replace('e', '*')
'I lik* b*auty'
>>> say.replace('e', '*', 1)
'I lik* beauty'

rfind 找到左数在最右边匹配到的指定字符的索引

>>> say = 'I like beauty'
>>> say.rfind('e')
8

split 字符串分割(默认按空格分割)

>>> say = 'I like beauty'
>>> say.split()
['I', 'like', 'beauty']

splitlines 按换行分割

>>> say = 'I like beauty
Yes!'
>>> say.splitlines()
['I like beauty', 'Yes!']

title 各单词首字母大写

>>> say = 'I like beauty'
>>> say.title()
'I Like Beauty'

zfill 用0在前面补位

>>> say = 'I like beauty'
>>> say.zfill(20)
'0000000I like beauty'

 打印的字符串变色

like = 'I like 33[31;1mbeauty33[0m'
print(like)
I like beaut # beauty会变红