Python3：string中的split()函数

Python3：string中的split()函数

Python2.x中split()函数：

>>> help(str.split)
Help on method_descriptor:

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

Return a list of the words in the string S, using sep as the
delimiter string.  If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are removed
from the result.

Python3.x中split()函数：

>>> help(str.split)
Help on method_descriptor:

split(...)
S.split(sep=None, maxsplit=-1) -> list of strings

Return a list of the words in S, using sep as the
delimiter string.  If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are
removed from the result.

样例：

>>> str = "this is string example....wow!!!"
>>> print (str.split( ))
['this', 'is', 'string', 'example....wow!!!']
>>> print (str.split('i',1))
['th', 's is string example....wow!!!']
>>> print (str.split('w'))
['this is string example....', 'o', '!!!']

>>> mySent='This book is the best book on Python or M.L. I have ever laid eyes upon'
>>> mySent.split()                                      #不带参数切分
['This', 'book', 'is', 'the', 'best', 'book', 'on', 'Python', 'or', 'M.L.', 'I', 'have', 'ever', 'laid', 'eyes', 'upon']
>>> import re
>>> regEx = re.compile('\\W')                               #正则表达式，定义分隔符是除单词、数字外的任意字符串
>>> listOfTokens = regEx.split(mySent)                      #根据正则表达式的规则进行切分
>>> listOfTokens
['This', 'book', 'is', 'the', 'best', 'book', 'on', 'Python', 'or', 'M', 'L', '', 'I', 'have', 'ever', 'laid', 'eyes', 'upon']
>>> [tok for tok in listOfTokens if len(tok) > 0]           #去掉空格
['This', 'book', 'is', 'the', 'best', 'book', 'on', 'Python', 'or', 'M', 'L', 'I', 'have', 'ever', 'laid', 'eyes', 'upon']
>>> [tok.lower() for tok in listOfTokens if len(tok) > 2]   #全部小写，去掉长度小于3的单词
['this', 'book', 'the', 'best', 'book', 'python', 'have', 'ever', 'laid', 'eyes', 'upon']