python字符串

字符串操作

特性：不可修改

name='li lian jie'

name.capitalize()#首字母大写

name='Cheng Long'

name.casefold()#大写全部变小写

name.center(20,"-")#输出：-----Cheng Long-----

name.count('n')#统计字符n出现的次数

name.encode()#将字符串编码成bytes格式

name.endswith('g')#判断字符串是否已g结尾

('c	l').expandtabs(10)#输出：c         l

name.find('n')#查找A，找到返回其索引，找不到返回-1

format使用：

msg="Today is good day?{} or {}"

print(msg.format('yes','no'))#输出Today is good day?yes or no

msg="Today is good day?{1} or {0}"

print(msg.format('yes','no'))#Today is good day?no or yes

msg="Today is good day?{yes} or {no}"

print(msg.format(yes='是',no='不是'))#输出Today is good day?是 or 不是

format_map使用:

msg="Today is good day?{yes} or {no}"

print(msg.format_map({'yes':'是','no':'不是'}))

#输出Today is good day?是 or 不是

msg.index('i')#输出 6

'9aA'.isalnum() #True  方法检测字符串是否由字母和数字组成。

#单纯字母或数字也可以，小数不行

print('9'.isdigit())# 是否整数

print('0'.isnumeric())#返回 Boolean 值，指出表达式的运算结果是否为数。

print('---'.join(['cheng','long']))#cheng---long

intab="abcde"


outtab='12345'


str="my name is acbde"


trantab=str.maketrans(intab,outtab)


print(str.translate(trantab))#输出my n1m5 is 13245


msg="Today is good day?{1} or {0}"


print(msg.partition('is'))#输出('Today ', 'is', ' good day?{1} or {0}')

print(msg.swapcase())#大小写互换 输出tODAY IS GOOD DAY?{1} OR {0}

print(msg.replace('Today','昨天'))#输出：昨天 is good day?{1} or {0}

print(msg.zfill(40))#凑40位，不够的补零 输出：000000000000Today is good day?{1} or {0}

print(msg.ljust(40,"-"))#右边补充Today is good day?{1} or {0}------------

print(msg.rjust(40,"-")#左边补充------------Today is good day?{1} or {0}

c='fasljf'


print(c.isidentifier()) #检测一段字符串可否被当作标志符，即是否符合变量命名规则 输出：True

ascii码表剩余的空间对应