python中字元串函數的用法_python中字元串内置函數的用法總結

capitalize（） 首字母大寫

a='someword'

b=a.capitalize()

print(b)

—>Someword

casefold()&lower() 所有字母變小寫，casefold可将未知字元便小寫

a='someWORD'

b=a.casefold()

print(b)

c=a.lower()

print(c)

—>someword

—>someword

center(width,fillchar=None) 設定寬度，并将内容居中，空白未知填充，一個字元

a='someword'

b=a.center(30,'*')

print(b)

count(sub,start=None,end=None) 去字元串中尋找，尋找子序列的出現次數，可指定起止點

a='somewordsomeword'

b=a.count(‘or')

print(b)

—>2

startswith(suffix,start=None,end=None)&endswith(suffix,start=None,end=None) 是否以XX開始/結束，可指定起止點

a='somewordsomeword'

b=a.startswith(‘sa')

c=a.endswith(‘ord')

print(b)

print(c)

—>False

—>True

find(sub,start=None,end=None) 尋找指定字元或字元串，并傳回第一個位置，找不到傳回-1，可指定起止點

a='somewordsomeword'

b=a.find(‘me')

print(b)

—>2

format() 格式化，将一個字元串中的占位符替換為指定的值

test='I am {name},age {a}'

v=test.format(name='alex',a=19)

print(v)

—>i am alex,age 19

format_map() 格式化，傳入的值

test='iam{name},age{a}'

v=test.format_map({“name”:'alex',”a”:19})

print(v)

—>i am alex,age 19

isalnum() 字元串中是否隻包含字母和數字

a='asdfs123*'

b=a.isalnum()

print(b)

—>False

expandtabs(tabsize=number) 将字元串以number分割，并将tab補入

a='asdfs123\t523fgbdf'

b=a.expandtabs(5)

print(b)

—>asdfs123 523fgbdf

isalpha() 字元串中是隻包含字母

a='asdfsfgbdf'

b=a.isalpha()

print(b)

—>True

isdecimal()&isdigit()&isnumeric() 字元串中是隻包含數字，isdigit更為強大，isnumeric還可識别中文

a='132132②二'

b=a.isdecimal()

c=a.isdigit()

d=a.isnumeric()

print(b)

print(c)

print(d)

—>False

—>False

—>True

isprintable() 是否存在不可顯示的字元如換行符

a='sdfgdfg\t'

b=a.isprintable()

print(b)

—>False

isspace() 判斷是否全部為空格

a='dsvsdv'

b=a.isspace()

print(b)

—>False

istitle()&title() 判斷是否為标題，即首字母大寫&變為标題

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) 将字元串中的每個元素按照指定分隔符進行拼接

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) 向右/左填充字元

a='hello'

b=a.ljust(20,'*')

c=a.rjust(20,'*')

print(b)

print(c)

—>hello***************

—>***************hello

islower()&lower() 判斷是是否為全小寫&變為全部小寫

a='Hello'

b=a.islower()

c=a.lower()

print(b,c)

—>False hello

isupper()&c=a.upper() 判斷是是否為全大寫&變為全部大寫

a='Hello'

b=a.isupper()

c=a.upper()

print(b,c)

—>False HELLO

lstrip(chars=None)&rstrip(chars=None)&strip(chars=None) 去除字元串左邊/右邊/兩邊的字元串，預設空格，換行等

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) 按maketrans對應關系将translate中的字元串進行替換

a='asdgfrfbcvzxrentas'

b=str.maketrans(‘xdsa','1234')

c=a.translate(b)

print(c)

—> 432gfrfbcvz1rent43

partition(sep)&rpartition(sep) 将字元串按指定字元分割成3段/或從右開始

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) 将字元串按指定字元串分割，分割後不保留

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) 按照換行符進行分割，帶true參數保留換行符

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) 判斷字元串是否以指定字元開始/結束，可指定起止點

a='aefsfsfeeav'

b=a.startswith(‘ae')

c=a.endswith(‘av',1,9)

print(b)

print(c)

True

—>False

swapcase() 小寫轉變為大寫

a='aefsfsfeeav'

b=a.swapcase()

print(b)

—>AEFSFSFEEAV

本文标題: python中字元串内置函數的用法總結

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