字符串方法

find,join,lower,replace,split,strip,translate

In [90]: s='apple,peach,banana,peach,pear'

In [91]: s.find('peach')
Out[91]: 6

In [92]: s.find('peach',7)
Out[92]: 19

In [93]: s.find('peach',7,18)
Out[93]: -1

In [94]: s.find('p')
Out[94]: 1

In [95]: s.rfind('p')
Out[95]: 25

In [96]: s.index('ban')
Out[96]: 12

In [97]: s.index('beauty')
Traceback (most recent call last):

  File "<ipython-input-97-cbc84c2c1291>", line 1, in <module>
    s.index('beauty')

ValueError: substring not found

In [98]: s.count('p')
Out[98]: 5

In [99]: s.conut('beauty')
Traceback (most recent call last):

  File "<ipython-input-99-097b6137e8f2>", line 1, in <module>
    s.conut('beauty')

AttributeError: 'str' object has no attribute 'conut'

In [1]: t='2019-10-27'

In [2]: t.split('-')
Out[2]: ['2019', '10', '27']                 分隔后的结果是列表

In [7]: list(map(int,t.split('-')))
Out[7]: [2019, 10, 27]

In [8]: s='apple,peach,banana,pear'

In [9]: s.split(',')
Out[9]: ['apple', 'peach', 'banana', 'pear']

In [10]: q='apple
peach	bananafpear orange'   不指定分隔符，则字符串中的任何空白符号（空格，换行符，制表符等）都被认为是分隔符

In [11]: q.split()
Out[11]: ['apple', 'peach', 'banana', 'pear', 'orange']

In [14]: s.split(',',maxsplit=1)
Out[14]: ['apple', 'peach,banana,pear']        指定最大分隔次数

In [15]: s='apple peace banana pear'

In [16]: s.split()

Out[16]: ['apple', 'peace', 'banana', 'pear']

In [17]: s1='apple peace bananaf pear'   不指定分隔符分化，认为多个连续分隔符是一个分隔符

In [18]: s1.split()

Out[18]: ['apple', 'peace', 'banana', 'pear']

In [19]: s='apple,,,peach,,,banana,,pear'     

In [22]: s2='apple,,,peach,,,banana,,pear'

In [23]: s2.split(',')

Out[23]: ['apple', '', '', 'peach', '', '', 'banana', '', 'pear']   指定分隔符的化，每个都是分隔符

In [25]: l=['abc','qwe','asd','bhy']     join（）方法将列表中多个字符串进行连接，并在相邻两个字符串之间插入指定字符，返回新字符串

In [26]: ','.join(l)
Out[26]: 'abc,qwe,asd,bhy'

In [27]: '**'.join(l)
Out[27]: 'abc**qwe**asd**bhy'


In [29]: ''.join(l)
Out[29]: 'abcqweasdbhy'

In [30]: m='how old are you'

In [31]: m.upper()
Out[31]: 'HOW OLD ARE YOU'

In [32]: m.title()
Out[32]: 'How Old Are You'

In [33]: m.capitalize()
Out[33]: 'How old are you'

In [34]: M='HOW OLD ARE YOU'

In [35]: M.lower()
Out[35]: 'how old are you'

In [37]: Mm='HOW OLD are You'

In [38]: Mm.swapcase()
Out[38]: 'how old ARE yOU'

In [39]: Mm='HOW OLD are You'

In [40]: Mm.replace('OLD','mmmm')     查找并且替换，每次只能替换一个
Out[40]: 'HOW mmmm are You'

In [41]: Mm='    HOW OLD are You    '

In [42]: Mm.strip()
Out[42]: 'HOW OLD are You'

In [43]: Mm.rstrip()
Out[43]: '    HOW OLD are You'

In [44]: asd='aasssddmmmmmmmasd'

In [45]: asd.strip('asd')
Out[45]: 'mmmmmmm'

In [49]: Mm='HOW OLD are You'

In [50]: Mm.startswith('HO')
Out[50]: True

In [51]: Mm.endswith('You')
Out[51]: True

In [52]: '123abc'.isalnum()   字母或数字
Out[52]: True

In [53]: '123'.isdigit()            数字
Out[53]: True

In [54]: "abc".isalpha()              字母
Out[54]: True

In [55]: 'high school'.center(20)
Out[55]: '    high school     '

In [56]: 'high school'.center(20,'%')
Out[56]: '%%%%high school%%%%%'

In [57]: 'high school'.ljust(20)
Out[57]: 'high school         '

In [58]: 'high school'.rjust(20)
Out[58]: '         high school'