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  • Python str内部功能介绍

    def capitalize(self):
    str = 'aGe'
    print(str.capitalize())
    结果:Age
    结论:首字母大写,其他字母都小写


    def casefold(self):
    str = 'AGE-age'
    print(str.casefold())
    结果:age-age
    结论:首字母大写,其他字母都小写

    def center(self, width, fillchar=None):
    str = 'AGE-age'
    print(str.center(20,'='))
    结果:======AGE-age=======
    结论:字符串str放在长为20的字符中,缺少的用fillchar字符来填充

    def count(self, sub, start=None, end=None):
    str = 'AGE-age'
    print(str.count('ag'))
    print(str.count('ag',5,6))
    结果:1、0
    结论:统计在字符串中出现特定字符的次数,也可以指定起始位置

    def encode(self, encoding='utf-8', errors='strict'):
    def endswith(self, suffix, start=None, end=None): 
    str = 'chian'
    print(str.endswith('an',3,5))
    结果:True
    结论:返回是否以特定字符结尾的字符串,可以指定起始位置

    def expandtabs(self, tabsize=None):
    str = "	alex"
    print (str.expandtabs())
    print(str.expandtabs(10))
    结果:        alex/          alex
    结论:缺省的tab键是8个空格,加数字为数字位的空格

    def find(self, sub, start=None, end=None):
    str = "alex is a workhard man"
    print (str.find('is'))
    print (str.find('or',4,13))
    结果:5/11
    结论:在字符串中查找字符,可以指定起始字符

    def format(*args, **kwargs):

    def index(self, sub, start=None, end=None):
    str = "alex is a workhard man"
    print (str.index('is'))
    结果:5
    结论:在字符串中查找字符位置,可以指定起始字符

    def isspace(self):
    #-*- coding:UTF-8 -*-
    str = ' fa'
    print(str.isspace())
    结果:False
    结论:要求字符串都是空串

    def istitle(self):
    str = "This Is String Example...Wow!!!"
    print (str.istitle())
    str = "This is string example....wow!!!"
    print (str.istitle())
    结果:True/False
    结论:只有首字母都是大写才是TITLE

    def join(self, iterable):
    str = "This Is String Example...Wow!!!"
    print (':'.join(str))
    str1 = ['This','is','a','book']
    print (':'.join(str1))
    str2 = ('This','is','a','book')
    print (':'.join(str2))
    str3 = {'1':'This','2':'is','3':'a','4':'book'}
    print ('-'.join(str3))

    结果:  

      T:h:i:s: :I:s: :S:t:r:i:n:g: :E:x:a:m:p:l:e:.:.:.:W:o:w:!:!:!
      This:is:a:book
      This:is:a:book
      2-4-1-3

    结论:用连接符把字符连接起来

    def ljust(self, width, fillchar=None):
    str1 = 'This is a book'
    print (str1.ljust(20,'#'))
    结果:This is a book######
    结论:左对齐,默认填充字符为空

    def maketrans(self, *args, **kwargs):
    import string
    str1 = 'abcde'
    map = str1.maketrans('abcde','12345')
    print (type(map))
    print (map)
    结果:

      <class 'dict'>
      {97: 49, 98: 50, 99: 51, 100: 52, 101: 53}

       结论:ASCII a-97,1-49

     def partition(self, sep):

    import string
    str = "http://www.w3cschool.cc/"
    print (str.partition('//'))

      结果:('http:', '//', 'www.w3cschool.cc/')

      结论:返回三个字符串,左边是分隔符左边的,右边是分隔符右边的,中间是分割符

    def replace(self, old, new, count=None):
    str = "http://www.w3cschool.cc//"
    print (str.replace('//','$$',1))
    print (str.replace('//','$$',2))
    结果:http:$$www.w3cschool.cc// http:$$www.w3cschool.cc$$
    结论:用新字符替换这些旧的字符
    def rfind(self, sub, start=None, end=None):
    str = "hello,alex,alpha"
    print (str.rfind('al',5,13))
    结果:11
    结论:找到最右边的这个字符,并且返回索引号
    def splitlines(self, keepends=None): 
    str = "Line1-a b c d e f
    Line2- a b c
    
    Line4- a b c d";
    print (str.splitlines( ))
    print (str.splitlines( 0 ))
    print (str.splitlines( 3 ))
    print (str.splitlines( 4 ))
    print (str.splitlines( 5 ))
    结果:

      ['Line1-a b c d e f', 'Line2- a b c', '', 'Line4- a b c d']
      ['Line1-a b c d e f', 'Line2- a b c', '', 'Line4- a b c d']
      ['Line1-a b c d e f ', 'Line2- a b c ', ' ', 'Line4- a b c d']
      ['Line1-a b c d e f ', 'Line2- a b c ', ' ', 'Line4- a b c d']
      ['Line1-a b c d e f ', 'Line2- a b c ', ' ', 'Line4- a b c d']

        结论:返回一个包含各行作为元素的列表



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  • 原文地址:https://www.cnblogs.com/python-study/p/5437259.html
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