Introduction to the usage of built-in string functions in python (code)

This article brings you an introduction to the usage of built-in string functions in python (code). It has certain reference value. Friends in need can refer to it. I hope it will be useful to you. Helps.

capitalize（） Capitalize the first letter

  a=’someword’ 
    b=a.capitalize() 
    print(b) 
    —>Someword

casefold()&lower() changes all letters to lowercase, casefold can lowercase unknown characters

 a=’someWORD’ 
    b=a.casefold() 
    print(b) 
    c=a.lower() 
    print(c) 
    —>someword 
    —>someword

center(width,fillchar=None) Set the width and center the content, blank unknown filling, one character

a=’someword’ 
    b=a.center(30,’*’) 
    print(b)

count(sub,start=None,end=None ) Search in the string to find the number of occurrences of the subsequence. You can specify the starting and ending points

  a=’somewordsomeword’ 
    b=a.count(‘or’) 
    print(b) 
    —>2

startswith(suffix,start=None,end=None)&endswith(suffix,start=None,end=None) Whether to start/end with XX, you can specify the start and end points

a=’somewordsomeword’ 
    b=a.startswith(‘sa’) 
    c=a.endswith(‘ord’) 
    print(b) 
    print(c) 
    —>False 
    —>True

find(sub,start=None,end=None) Find the specified character or string and return the first position. If not found, it returns -1. You can specify the starting and ending points

 a=’somewordsomeword’ 
    b=a.find(‘me’) 
    print(b) 
    —>2

format () Formatting, replace the placeholders in a string with the specified value

test=’I am {name},age {a}’ 
    v=test.format(name=’alex’,a=19) 
    print(v) 
    —>i am alex,age 19

format_map() Formatting, the passed in value

 test=’iam{name},age{a}’ 
    v=test.format_map({“name”:’alex’,”a”:19}) 
    print(v) 
    —>i am alex,age 19

isalnum () Whether the string only contains letters and numbers

 a=’asdfs123*’ 
    b=a.isalnum() 
    print(b) 
    —>False

expandtabs(tabsize=number) Split the string by number and fill in the tab

   a=’asdfs123\t523fgbdf’ 
    b=a.expandtabs(5) 
    print(b)
    —>asdfs123  523fgbdf

isalpha () The string contains only letters

   a=’asdfsfgbdf’ 
    b=a.isalpha() 
    print(b) 
    —>True

isdecimal()&isdigit()&isnumeric() The string contains only numbers, isdigit is more powerful, isnumeric can also recognize Chinese

 a=’132132②二’ 
    b=a.isdecimal() 
    c=a.isdigit() 
    d=a.isnumeric() 
    print(b) 
    print(c) 
    print(d) 
    —>False 
    —>False 
    —>True

isprintable() Whether there are non-displayable characters such as line breaks

   a=’sdfgdfg\t’ 
    b=a.isprintable() 
    print(b) 
    —>False

isspace() Determine whether all are spaces

 a=’dsvsdv’ 
    b=a.isspace() 
    print(b) 
    —>False

istitle()&title() Determine whether it is a title, that is, the first letter is capitalized & becomes the title

a=’follow uncased characters and lowercase characters only cased ones’ 
    b=a.istitle() 
    print(b) 
    c=a.title() 
    print(c) 
    —>False 
    —>Follow Uncased Characters And Lowercase Characters Only Cased Ones

join(iterable) Splice each element in the string according to the specified delimiter

a=’一二三四五六七’ 
    print(a) 
    b=’*’ 
    c=b.join(a) 
    print(c) 
    —>一二三四五六七 
    —>一二三四五六七

ljust(width,fillchar=None)&rjust(width,fillchar=None) Fill characters to the right/left

  a=’hello’ 
    b=a.ljust(20,’*’) 
    c=a.rjust(20,’*’) 
    print(b) 
    print(c) 
    —>hello*************** 
    —>***************hello

islower()&lower() Determine whether it is full Lowercase & changes to all lowercase

 a=’Hello’ 
    b=a.islower() 
    c=a.lower() 
    print(b,c) 
    —>False hello

isupper()&c=a.upper() Determine whether it is all uppercase & changes to all uppercase

a=’Hello’ 
    b=a.isupper() 
    c=a.upper() 
    print(b,c) 
    —>False HELLO

lstrip(chars =None)&rstrip(chars=None)&strip(chars=None) Remove strings on the left/right/both sides of the string, default spaces, newlines, etc.

a=’Hello’ 
    b=a.lstrip() 
    c=a.rstrip() 
    d=a.strip() 
    print(b) 
    print(c) 
    print(d) 
    —>Hello  
    —> Hello 
    —>Hello

maketrans(*args,**kwargs )&translate(table) Replace the string in translate according to the maketrans correspondence

a=’asdgfrfbcvzxrentas’ 
    b=str.maketrans(‘xdsa’,’1234’) 
    c=a.translate(b) 
    print(c) 
    —> 432gfrfbcvz1rent43

partition(sep)&rpartition(sep) Split the string into 3 segments according to the specified characters/or start from the right

a=’helwloasvxcwaewc’ 
    b=a.partition(‘w’) 
    c=a.rpartition(‘w’) 
    print(b) 
    print(c) 
    —>(‘hel’, ‘w’, ‘loasvxcwaewc’) 
    —>(‘helwloasvxcwae’, ‘w’, ‘c’)

split(sep=None,maxsplit=-1)&rsplit(sep=None,maxsplit=-1) Split the string according to the specified string and do not retain it after splitting

a=’helwloasvxcwaewc’ 
    b=a.split(‘w’,2) 
    c=a.rsplit(‘w’) 
    print(b) 
    print(c) 
    —>[‘hel’, ‘loasvxc’, ‘aewc’] 
    —>[‘hel’, ‘loasvxc’, ‘ae’, ‘c’]

splitlines(keepends=None) Split according to newlines, with true parameter to keep newlines

a=’helwloas\nvxcwaewc\nafgasdfs’ 
    b=a.splitlines() 
    c=a.splitlines(True) 
    print(b) 
    print(c) 
    —>[‘helwloas’, ‘vxcwaewc’, ‘afgasdfs’] 
    —>[‘helwloas\n’, ‘vxcwaewc\n’, ‘afgasdfs’]

startswith(prefix,start=None,end=None)&endswith(prefix,start=None, end=None) Determine whether the string starts/ends with the specified character, you can specify the starting and ending points

a=’aefsfsfeeav’ 
    b=a.startswith(‘ae’) 
    c=a.endswith(‘av’,1,9) 
    print(b) 
    print(c) 
    True 
    —>False

swapcase() Convert lowercase to uppercase

 a=’aefsfsfeeav’ 
    b=a.swapcase() 
    print(b) 
    —>AEFSFSFEEAV

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