学步园

>>> '%-*s' % (10, 'hello')
'hello     '
>>> '%*s' % (10, 'hello')
'     hello'
- 代表左对齐
*后面括号中有数字，代表长度  

append()
len()

find(sub[, start[, end]]) 返回最先找到的sub的索引，若查找失败则返回-1

S.replace(old, new [, count]) -> string

str.split([sep [,maxsplit]]) -> list of strings

>>> line = '1,2,3,4,5,6'
>>> line.split(',')
['1', '2', '3', '4', '5', '6']
>>> line.split(',', 4)
['1', '2', '3', '4', '5,6']
>>> line.rsplit(',', 4)
['1,2', '3', '4', '5', '6']

str.strip() #Return a copy of the string S with leading and trailing whitespace removed.
rstrip() #Return a copy of the string S with trailing whitespace removed.
lstrip() #Return a copy of the string S with leading whitespace removed.

center(...)
    S.center(width[, fillchar]) -> str

>>> s.ljust(10, 'x')
'1.2xxxxxxx'
>>> s.rjust(10, 'x')
'xxxxxxx1.2'
>>> s.center(10, 'x')
'xxx1.2xxxx'

rpartition(...)
    S.rpartition(sep) -> (head, sep, tail)
    
    Search for the separator sep in S, starting at the end of S, and return
    the part before it, the separator itself, and the part after it.  If the
    separator is not found, return two empty strings and S.

>>> str = 'hello world'
>>> str.rpartition(' ') 
('hello', ' ', 'world')
>>> str.partition(' ')
('hello', ' ', 'world')
>>> str.rpartition('l')  #只分一次
('hello wor', 'l', 'd')
>>> str.partition('l') #返回tuple，并且显示分隔的sep
('he', 'l', 'lo world')
>>> str.split(' ') #返回 list
['hello', 'world']

好像没有什么区别？

isdigit(...)
    S.isdigit() -> bool
    
    Return True if all characters in S are digits
    and there is at least one character in S, False otherwise
isnumeric(...)
    S.isnumeric() -> bool
    
    Return True if there are only numeric characters in S,
    False otherwise.
    

#返回大小写相互转化的结果
>>> line = 'HellO WOrld'
>>> line.swapcase()
'hELLo woRLD'

#字符串左边填充0
>>> line.zfill(15)
'0000HellO WOrld'   

S.expandtabs([tabsize]) -> str
The default tabsize is 8.
>>> line
'a\tb\tc'
>>> line.expandtabs()
'a       b       c'

并没有iscapitalize函数，不过可以自己实现：

def iscapitalize(s):
   return s == s.capitalize()

>>> a = 'hello world'
>>> a.capitalize()
'Hello world'
>>> a.title()
'Hello World'
>>> a  = 'Hello world'
>>> a.istitle()
False
>>> a  = 'Hello World'
>>> a.istitle()
True

3.X中实现：

>>> map = str.maketrans('he', 'sh')
>>> str.translate(map)
'shllo world'
>>> str
'hello world'

2.X中下面的方法可靠，但在3.X中不行

string.maketrans(from, to) #from to must have the same length.
string.translate(s, table[, deletechars])
str.translate(table[, deletechars])
unicode.translate(table)

>>> import string
>>> map = string.maketrans('123', 'abc')
>>> s = '2341321234232123'
>>> s.translate(map)
'bc4acbabc4bcbabc'

import string 
def translator(frm='', to='', delete='', keep=None): 
if len(to) == 1: 
        to = to * len(frm) 
    trans = string.maketrans(frm, to) 
    if keep is not None: 
        allchars = string.maketrans('', '') 
        delete = allchars.translate(allchars, keep.translate(allchars,delete))
    def translate(s): 
        return s.translate(trans, delete) 
    return translate