Python string manipulation

First, intercept the string

Str[0:3] #截取第一位到第三位的字符

str[:] #截取字符串的全部字符

Str[6:] #截取第七个字符到结尾

Str[:-3] #截取从头开始到倒数第三个字符之前

STR[2] #截取第三个字符

STR[-1] #截取倒数第一个字符

STR[::-1] #创造一个与原字符串顺序相反的字符串

STR[-3:-1] #截取倒数第三位与倒数第一位之前的字符

Str[-3:] #截取倒数第三位到结尾

Str[:-5:-3] #逆序截取

Second, delete: Show only letters and numbers

def onlycharnum (s,oth= "):

S2 = S.lower ();

Fomart = ' abcdefghijklmnopqrstuvwxyz0123456789 '

For C in S2:

If not C in Fomart:

s = S.replace (c, ");

return s;

Print (Onlystr ("a000 aa-b"))

Third, scan string

S1 = ' Cekjgdklab '

S2 = ' Gka '

NPos =-1

For C in S1:

If C in S2:

NPos = S1.index (c)

Break

Print (NPos)

Four, go to space and special symbol: S.strip (). Lstrip (). Rstrip (', ')

Five

mystr = "Hello World Sky 123"

S1 = ' Sky '

Len (MyStr and S1)

MyStr = Mystr[::-1]

mystr = mystr[::-1]                                    #翻转字符串
Mystr.find (S1)                                            #
Mystr.index (S1)                                         #

MyStr + = S1 #连接字符串, connect S1 to mystr; connect string of specified length: MyStr + = S1[0:n]

Mystr.find (S1) #find从左向右查字符串, returns a subscript when found, returns 1 when not found, does not affect the execution of the program
Mystr.index (S1) #index从左向右查字符串, when found to return subscript, can not find the times wrong, affecting the execution of the program
Mystr.rfind (S1) #rfind从右向左查字符串, returns a subscript when found, returns 1 when not found, does not affect the execution of the program
Mystr.rindex (S1) #rindex从右向左查字符串, when found to return subscript, can not find the times wrong, affecting the execution of the program
Mystr.count (S1) #计算mystr字符串中s1字符串的个数, returns 0 when not present
Mystr.replace ("World", "World", 2) #替换字符串, because the string is non-modifiable, the result of the output is new, the original mystr has not been modified. The string has more than one default all modified, and if the third parameter has a number, it is replaced a few times.
Mystr.split ("") #分号中是从字符串中选取的用作切割的东西, but this thing is lost after the separation.
Mystr.capitalize () #让字符串开头第一个字符大写.
Mystr.title () #让字符串中的所有单词第一个字母都大写.
Mystr.startswith (S1) #判断是否以s1开头, returns True and False
Mystr.endswith (S1) #判断是否以s1结尾, returns True and False
Mystr.upper () #将所有字母都变成大写.
Mystr.lower () #将所有字母都变成小写.
Mystr.center (#总共50字符位置) to center the MYSTR string
Mystr.ljust (#左对齐)
Mystr.rjust (#右对齐)
Mystr.lstrip () #去掉左边的空格
Mystr.rstrip () #去掉右边的空格
Mystr.strip () #去掉两边的空格
Mystr.partition ("and") #以and为中心, is divided into three parts, and itself is the middle part.
Mystr.rpartition ("Itcast") #若是有多个字符, with the right character as the benchmark
Mystr.splitlines () #若是字符串中有换行符 (such as a poem), a newline character will be used as a split, output way dictionary.
Mystr.isalpha () #判断是不是纯字母
Mystr.isdigit () #判断是否为纯数字
Mystr.isalnum () #判断是否只包含字母和数字
Mystr.isspace () #判断是否为纯空格
A = "_"

b = ["AA", "BB", "CC"]
A.join (b) #将b中的元素以a中的内容连接起来

Content = "LSA Fdsfds ds SDFs \t\t\t J ds d FSD fds FDS"
A = Content.split ()
Print (a) #如果括号里什么都没有, by default, splits strings with spaces and tabs.

Python string manipulation