python之字符串函数

1 # 以什么什么结尾
2 # 以什么什么开始
3 test = "alex"
4 v = test.endswith('ex')
5 v = test.startswith('ex')
6 print(v)

1 test = "1\t2345678\t9"
2 v = test.expandtabs(6)
3 print(v,len(v))

1 # 从开始往后找，找到第一个之后，获取其未知
2 # > 或 >=
3 test = "alexalex"
4 # 未找到 -1
5 v = test.find('e')
6 print(v)

1 # index找不到，报错   忽略
2 test = "alexalex"
3 v = test.index('a')
4 print(v)

 1 # 格式化，将一个字符串中的占位符替换为指定的值
 2 test = 'i am {name}, age {a}'
 3 print(test)
 4 v = test.format(name='alex',a=19)
 5 print(v)
 6 
 7 test = 'i am {0}, age {1}'
 8 print(test)
 9 v = test.format('alex',19)
10 print(v)
11 
12 # 格式化，传入的值 {"name": 'alex', "a": 19}
13 test = 'i am {name}, age {a}'
14 v1 = test.format(name='df',a=10)
15 print(v1)
16 v2 = test.format_map({"name": 'alex', "a": 19})
17 print(v2)

1 # 字符串中是否只包含 字母和数字
2 test = "er;"
3 v = test.isalnum()
4 print(v)

1 test = "sqy"
2 v = test.capitalize()
3 print(v)

1 test = "sqy"
2 v1 = test.casefold()
3 print(v1)
4 v2 = test.lower()
5 print(v2)

1 # 20 代指总长度
2 # *  空白未知填充，一个字符，可有可无
3 test = "sqy"
4 v = test.center(20,"中")
5 print(v)

 1 # test = "alex"
 2 # v = test.ljust(20,"*")
 3 # print(v)
 4 
 5 # test = "alex"
 6 # v = test.rjust(20,"*")
 7 # print(v)
 8 
 9 # test = "alex"
10 # v = test.zfill(20)
11 # print(v)

1 test = "aLexalexr"
2 v = test.count('ex')
3 print(v)
4 
5 test = "aLexalexr"
6 v = test.count('ex',5,6)
7 print(v)

1 test = "as大多数df"
2 v = test.isalpha()
3 print(v)

1 test = "②" # 1，②,儿
2 v1 = test.isdecimal()
3 v2 = test.isdigit()
4 v3 = test.isnumeric()
5 print(v1,v2,v3)

1 # \t   制表符
2 # \n   换行
3 test = "gdds\tfdsfd"
4 v = test.isprintable()
5 print(v)

1 test = "  ass"
2 v = test.isspace()
3 print(v)

1 test = "Return True if all cased characters in S are uppercase and there is"
2 v1 = test.istitle()
3 print(v1)
4 v2 = test.title()
5 print(v2)
6 v3 = v2.istitle()
7 print(v3)

1 test = "你是风儿我是沙"
2 print(test)
3 t = ' '
4 v = "_".join(test)
5 print(v)

1 test = "Alex"
2 v1 = test.islower()
3 v2 = test.lower()
4 print(v1, v2)
5 
6 v1 = test.isupper()
7 v2 = test.upper()
8 print(v1,v2)

 1 test = "\nxas12xa\n\txax1221axa  "
 2 v = test.lstrip('xa')
 3 v = test.rstrip('9lexxexa')
 4 v = test.strip('xa')
 5 print(v)
 6 
 7 test.lstrip()
 8 test.rstrip()
 9 test.strip()
10 # 去除左右空白
11 v = test.lstrip()
12 v = test.rstrip()
13 v = test.strip()
14 print(v)
15 print(test)
16 # 去除\t \n
17 v = test.lstrip()
18 v = test.rstrip()
19 v = test.strip()
20 print(v)

1 v = "asidufkasd;fiuadkf;adfkjalsdjf"
2 m = str.maketrans("aeiou", "12345")
3 new_v = v.translate(m)
4 print(new_v)

1 test = "testasdsddfg"
2 v = test.partition('s')
3 print(v)
4 v = test.rpartition('s')
5 print(v)

 1 test = "sqys"
 2 v = test.split('s',2)
 3 print(v)
 4 v = test.rsplit()
 5 print(v)
 6 
 7 
 8 # 23 分割，只能根据，true，false：是否保留换行
 9 # test = "asdfadfasdf\nasdfasdf\nadfasdf"
10 # v = test.splitlines(False)
11 # print(v)

1 test = "aLex"
2 v = test.swapcase()
3 print(v)

1 a = "de12_f"
2 v = a.isidentifier()
3 print(v)

1 test = "alexalexalex"
2 v = test.replace("ex",'bbb')
3 print(v)
4 v = test.replace("ex",'bbb',2)
5 print(v)