python 字符串所有操作

python字符串操作:

字符串一般常用操作:

字符串的替换、删除、截取、复制、连接、比较、查找、分割等

字符串内置操作方法:

使用type获取创建对象的类 type(name)
使用dir获取类的成员dir(name)
使用vars获取类的成员和各个成员的值

字符串常用方法操作:

1:casefold()将所有的字符转化为小写:

name = "ZhangSan"
print("{0}".format(name.casefold()))
# 打印结果:zhangsan

2:capitalize()字符串首字母大写其他字符都小写:

name = "zhangSan"
name = name.capitalize()
print("{0}".format(name))
# 打印结果:Zhangsan

3:center()字符串宽度填充:

name = "zhangSan"
name = name.center(12)
print("{0}".format(name))
# 打印结果:'  Zhangsan  '
# 默认以空格填充

name = "zhangSan"
name = name.center(12, "#")
print("{0}".format(name))
# 打印结果:'##Zhangsan##'
# 以‘#’填充

4:count()统计字符在字符串中出现的次数:

name = "zhangSan"
num = name.count('S')
print("{0}".format(num))
# 打印结果:1

name = "zhangSan"
num = name.count('S', 0, 3) #从0，1，2索引里找
print("{0}".format(num))
# 打印结果:0

5:encode()字符串编码:

name = "zhangsan"
name = name.encode('gbk')
print("{0}".format(name))
# 打印结果:b'zhangsan'

6:startswith()判断字符串以某个字符串开头，返回boolean类型:

name = "zhangsan"
isTrue = name.startswith("zh")
print(isTrue)
# 打印结果:True

7:endswith()判断字符串以某个字符串结尾，返回boolean类型:

name = "zhangsan"
isTrue = name.endswith("san")
print(isTrue)
# 打印结果:True

8:find()在字符串中查找指定字符串，找不到时返回-1:

name = "zhangsan"
isIn = name.find("an")
print(isIn)
# 打印结果:2
# 返回字符串开始的下标

9:format()格式化输出字符串:

name = "{} {} zhangsan" #"{} {}"是占位符，用下边format()里边的参数填充
name = name.format('I', 'am')
print(name)
# 打印结果:I am zhangsan

10:index()在字符串中查找指定的字符串,找不到时直接报错:

name = "zhangsan"
isIn = name.index('h')
print(isIn)
# 打印结果:1

11:join()字符串连接：

name = "zhangsan"
name = '*'.join(name)
print(name)
# 打印结果:z*h*a*n*g*s*a*n

12:isalnum()判断字符串是否包含字母数字字符：

name = "zhangsan1"
isTrue = name.isalnum()
print(isTrue)
# 打印结果:True

name = "zhangsan1*"
isTrue = name.isalnum()
print(isTrue)
# 打印结果:False

13:isalpha()判断是否只包含字母:

name = "zhangsan"
isTrue = name.isalpha()
print(isTrue)
# 打印结果:True

name = "zhangsan1"
isTrue = name.isalpha()
print(isTrue)
# 打印结果:False

14:isdigit()判断字符串只由数字构成:

name = "1234"
isTrue = name.isdigit()
print(isTrue)
# 打印结果:True

name = "zhangsan1234"
isTrue = name.isdigit()
print(isTrue)
# 打印结果:False

15:isspace()判断字符串是否是空格:

name = " "
isTrue = name.isspace()
print(isTrue)
# 打印结果:True

name = "zhang san"
isTrue = name.isspase()
print(isTrue)
# 打印结果:False

16:isupper()判断字符串是否全是大写字符:

name = "ZHANGSAN"
isTrue = name.isupper()
print(isTrue)
# 打印结果:True

17:lower()将所有的大写字符转为小写字符:

name = "ZHANGSAN"
name = name.lower()
print(name)
# 打印结果:zhangsan

18:lstrip()去除字符串左边的空格:

name = "   zhangsan  "
name = name.lstrip()
print(name)
# 打印结果:zhangsan  

19:rstrip()去除字符串右边的空格:

name = "   zhangsan  "
name = name.rstrip()
print(name)
# 打印结果:   zhangsan

20:去除字符串2边的空格:

name = "   zhangsan   "
name = name.strip()
print(name)
# 打印结果:zhangsan

21:replace()字符串替换:

name = "zhangsan"
name = name.replace("zhang", "li")
print(name)
# 打印结果:lisan

22:split()字符串分割，默认是空格:

name = "zhang san"
name = name.split()
print(name)
# 打印结果:['zhang', 'san']

23:add()在字符串后边添加字符串:

name = "zhang"
name = name.__add__("san")
print(name)
# 打印结果:zhangsan

24:contains()判断指定字符串是否包含在字符串中:

name = "zhangsan"
isTrue = name.__contains__("san")
print(isTrue)
# 打印结果:True

25:eq（）判断字符串是否相等:

name = "zhangsan"
name1 = "zhangsan"
isEq = name.__eq__(name1)
print(isEq)
# 打印结果:True