Python Common String Functions

character-case transformations in strings

1. Str.lower ()//lowercase

>>> ' skate '. Lower ()
' Skate '

2. Str.upper ()//uppercase

>>> ' skate '. Upper ()
' Skate '

3. Str.swapcase ()//Case Swap

>>> ' skate '. Swapcase ()
' Skate '

4. Str.title ()//capital letter, remaining lowercase

>>> ' skate '. Title ()
' Skate '

The alignment of the string at output

1. Str.ljust (Width,[fillchar])//output width characters, str left-aligned, the insufficient portion is filled with Fillchar, the default is a space

>>> ' skate '. Ljust (10)
' Skate '
>>> ' skate '. Ljust (10, ' 0 ')
' skate00000 '

2. Str.rjust (Width,[fillchar])//output width characters, str right-aligned, the insufficient portion is filled with Fillchar, the default is a space

>>> ' skate '. Rjust (10, ' 0 ')
' 00000skate '
>>> ' skate '. Rjust (10)
' Skate '

3. Str.center (Width,[fillchar])//center alignment

>>> ' skate '. Center (10)
' Skate '
>>> ' Skate ' center (10, ' 0 ')
' 00skate000 '

4. Str.zfill (width)//The str into a width length, and right alignment, the less part with 0 complement

>>> ' skate '. Zfill (10)
' 00000skate '

String Search Related

Str.find (' t ')//search for specified string, no return-1
Str.find (' t ', start)//Specify start position search
Str.find (' t ', start,end)//Specify start and end position search:
Str.rfind (' t ')//search from the right
Str.count (' t ')//How many of the specified strings have been searched:

eg

>>> ' skate '. Find (' t ')
3
>>> ' skate '. Find (' t ', 2)
3
>>> ' skate '. Find (' t ', 2,4)
3
>>> ' skate '. RFind (' t ')
3
>>> ' skate '. Count (' t ')
1

String substitution

Str.replace (' old ', ' new ')//replace old as new
Str.replace (' old ', ' new ', maxreplacetimes)//Replace the specified number of old with new

eg

>>> ' skateskate '. Replace (' s ', ' s ')
' Skateskate '
>>> ' skateskate '. Replace (' s ', ' s ', 1)
' Skateskate '
>>>

String go to space and go to specify character

Str.strip ([chars])//Go to both sides of the chars, the default is a space
Str.lstrip ([chars])//go to the left chars, the default is a space
Str.rstrip ([chars])//Go to the right chars, the default is a space

Segmentation of strings

Str.split ([Sep, [maxsplit]])//with Sep as a delimiter, divide str into a list. Maxsplit represents the number of splits. The default delimiter is a blank character
Str.rsplit ([Sep, [Maxsplit]])
Str.splitlines ([keepends])//dividing str into a list,keepends is a bool value, and the row separator is preserved after each row is true.

eg

>>> ' Skateskate '. Split ()
[' Skateskate ']
>>> ' Skateskate '. Split (' E ')
[' Skat ', ' skat ', ']

>>> ' Skate skate '. Rsplit (")
[' Skate ', ' skate ']

>>> ' skate\n skate1 '. Splitlines ()
[' Skate ', ' skate1 ']
>>> ' skate\n skate1 '. Splitlines (1)
[' skate\n ', ' skate1 ']
>>>

String connection

Str.join (SEQ)//The sequence represented by SEQ (string sequence), connected with Str

eg

>>> ' skate '. Join (' 111 ')
' 1skate1skate1

String judgments

Str.startwith (Prefix[,start[,end])//whether to start with prefix
Str.endwith (Suffix[,start[,end])//whether end with suffix
Str.isalnum ()//is full of letters and numbers, and has at least one character
Str.isalpha ()//is full of letters and has at least one character
Str.isdigit ()//Is full number, and has at least one character
Str.isspace ()//is full of whitespace characters and has at least one character
Str.islower () whether the letters in//STR are all lowercase
Str.isupper () whether the letters in//STR are uppercase
Str.istitle ()//str If the letter is first capitalized

eg

>>> ' skate '. StartsWith (' s ')
True
>>> ' skate ' startswith (' s ')
False
>>> ' skate ' endswith (' s ')
False
>>> ' skate '. EndsWith (' e ', up)
False
>>> ' skate '. EndsWith (' e ', 1)
True
>>>

True
>>> ' skate '. Isalnum ()
True
>>> ' 222 '. Isalnum ()
True
>>> ' skate222 '. Isalnum ()
True
>>> ' Skate 222 '. Isalnum ()
False
>>>

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