Python String Methods 3

str.ljust(width[, fillchar])
>>> ‘    hello world‘.ljust(20)
‘    hello world     ‘
>>> ‘    hello world‘.ljust(20,‘=‘)
‘    hello world=====‘

>>> ‘HellO WorlD‘.lower()
‘hello world‘
>>> ‘HELLO WORLD‘.lower()
‘hello world‘
>>> ‘HelLO Wo123lD‘.lower()
‘hello wo123ld‘

>>> ‘    hello world‘.lstrip()
‘hello world‘
>>> ‘%%%hello world‘.lstrip(‘%‘)
‘hello world‘
>>> ‘%%%h%ello world‘.lstrip(‘%‘)
‘h%ello world‘

>>> ‘hello world‘.zfill(20)
‘000000000hello world‘
>>> ‘hello world‘.zfill(5)
‘hello world‘
>>> ‘%%%h%ello world‘.lstrip(‘%h‘)
‘ello world‘

>>> ‘hello%world‘.partition(‘%‘)
(‘hello‘, ‘%‘, ‘world‘)
>>> ‘hello world‘.partition(‘ ‘)
(‘hello‘, ‘ ‘, ‘world‘)
>>> ‘hello world‘.partition(‘&‘)
(‘hello world‘, ‘‘, ‘‘)

str.replace(old, new[, max])
>>> ‘hello world‘.replace(‘o‘,‘x‘)
‘hellx wxrld‘
>>> ‘hello world‘.replace(‘o‘,‘x‘,1)
‘hellx world‘
>>> ‘hello world‘.replace(‘o‘,‘x‘,3)
‘hellx wxrld‘

str.rfind(str, beg=0 end=len(string))
>>> ‘hello world‘.rfind(‘o‘)
7
>>> ‘hello world‘.rfind(‘x‘)
-1
>>> ‘hello world‘.rfind(‘o‘,0,5)
4

str.rindex(str, beg=0 end=len(string))
>>> ‘hello world‘.rindex(‘o‘)
7
>>> ‘hello world‘.rindex(‘x‘)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: substring not found
>>> ‘hello world‘.rindex(‘o‘,0,5)
4

str.split(str="", num=string.count(str)).
参数
str -- 分隔符，默认为所有的空字符，包括空格、换行(\n)、制表符(\t)等。
num -- 分割次数

>>> ‘hello world‘.split()
[‘hello‘, ‘world‘]
>>> ‘h e l l o  w\n orl d‘.split()
[‘h‘, ‘e‘, ‘l‘, ‘l‘, ‘o‘, ‘w‘, ‘orl‘, ‘d‘]
>>> ‘hello world‘.split(‘lo w‘)
[‘hel‘, ‘orld‘]

>>> ‘hel\rl\no w\n\norld‘.splitlines()
[‘hel‘, ‘l‘, ‘o w‘, ‘‘, ‘orld‘]
>>> ‘hel\rl\no w\n\norld‘.splitlines(True)
[‘hel\r‘, ‘l\n‘, ‘o w\n‘, ‘\n‘, ‘orld‘]

str.startswith(str, beg=0,end=len(string));
>>> ‘hello world‘.startswith(‘he‘)
True
>>> ‘hello world‘.startswith(‘hea‘)
False
>>> ‘ hello world‘.startswith(‘hea‘)
False
>>> ‘ hello world‘.startswith(‘he‘)
False

>>> ‘  hello world    ‘.strip(‘ hd‘)
‘ello worl‘
>>> ‘  hello world    ‘.strip(‘ hdl‘)
‘ello wor‘

>>> ‘Hello World‘.swapcase()
‘hELLO wORLD‘

>>> ‘hello world‘.title()
‘Hello World‘
>>> ‘ hello world‘.title()
‘ Hello World‘

注意:定义一个十进制字符串，只需要在字符串前添加 ‘u‘ 前缀即可。

>>> u‘hello world‘.isdecimal()
False
>>> u‘hello2 world‘.isdecimal()
False
>>> u‘343434‘.isdecimal()
True

str.translate(table[, deletechars]);
table -- 翻译表，翻译表是通过maketrans方法转换而来。
deletechars -- 字符串中要过滤的字符列表

#!/usr/bin/python

from string import maketrans   # Required to call maketrans function.

intab = "aeiou"
outtab = "12345"
trantab = maketrans(intab, outtab)

str = "this is string example....wow!!!";
print str.translate(trantab, ‘xm‘);
以上实例输出结果：

th3s 3s str3ng 21pl2....w4w!!!