python常用字符串函数

港控/mmm° 2022-04-22 03:22 293阅读 0赞

#字符串的操作
    tstr = 'hello this world hello another world.txt'
    print(tstr.find('ll'))  #从左边开始寻找  #2
    print(tstr.find('ww'))  # -1 , 没找到
    print(tstr.rfind('l'))  #从右边    #34
    print(tstr.rfind('.'))
    print(tstr[tstr.rfind('.'):])   # .txt 找出格式信息
    
    print(tstr.index('.'))  # 36, 不同于find ，index未找到匹配字符会报错
    
    print(tstr.count('w'))  # 2, 打印出子字符串在 字符串出现的个数
    
    tr = tstr.replace('hello', 'bye')
    print(tr)   # bye this world bye another world.txt
    
    print(tstr.split(sep=' ', maxsplit=3))  # ['hello', 'this', 'world', 'hello another world.txt']
    
    print(tstr.title())     #将每个首字母大写 Hello This World Hello Another World.Txt
    print(tstr.capitalize())    #只把首个首字母大写 Hello this world hello another world.txt
    
    print(tstr.startswith('th'))    #检查是否以 该字符串 开头 False
    print(tstr.endswith('txt')) #True
    
    print(tstr.upper().lower())     #先将全部字母转换成大写，再全部为小写
    
    tr1 = tstr.ljust(50)
    print(tr1)
    print(len(tr1)) # 50 , 返回与原字符串左对齐，右边增加空格， 长度为50的字符串
    print(len(tstr))    #40
    print(tstr.rjust(50))   #右对齐
    print(tstr.center(50))  #     hello this world hello another world.txt     居中
    
    tr2 = tstr.rjust(50)
    print(tr2)  #          hello this world hello another world.txt
    print(tr2.lstrip())     #hello this world hello another world.txt    #删除左边的空格
    print(tstr.center(50).strip())  #删除两端的空格
    
    print(tstr.partition('llo'))    #以 'llo' 为界，进行分割    #('he', 'llo', ' this world hello another world.txt')
    print(tstr.rpartition('llo'))   # ('hello this world he', 'llo', ' another world.txt')
    
    print(tstr.splitlines())    #依据行进行分割
    
    print(tstr.isalpha())   #是否是字母
    print(tstr.isalnum())   #所有是字母或数字
    print(tstr.isdigit())   #是否只包含数字
    print(tstr.isspace())   #空格
    print(tstr)
    print('tstr'.isidentifier())    #是否是字母开头
    
    str3 = ','
    str = ['helo', 'this', 'world']
    print(str3.join(str))   # helo,this,world
    
    tstr = tstr.split(sep=' ')
    print(tstr) #    ['hello', 'this', 'world', 'hello', 'another', 'world.txt']
    print(str3.join(tstr))  # hello,this,world,hello,another,world.txt

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