python字符串分析演练
在空格中拆分字符串,获取列表,显示其类型,打印:
el@apollo:~/foo$ python
>>> mystring = "What does the fox say?"
>>> mylist = mystring.split(" ")
>>> print type(mylist)
<type 'list'>
>>> print mylist
['What', 'does', 'the', 'fox', 'say?']
如果相邻有两个分隔符,则假定为空字符串:
el@apollo:~/foo$ python
>>> mystring = "its so fluffy im gonna DIE!!!"
>>> print mystring.split(" ")
['its', '', 'so', '', '', 'fluffy', '', '', 'im', 'gonna', '', '', '', 'DIE!!!']
在下划线上拆分一个字符串并抓取列表中的第5项:
el@apollo:~/foo$ python
>>> mystring = "Time_to_fire_up_Kowalski's_Nuclear_reactor."
>>> mystring.split("_")[4]
"Kowalski's"
将多个空间折叠为一个
el@apollo:~/foo$ python
>>> mystring = 'collapse these spaces'
>>> mycollapsedstring = ' '.join(mystring.split())
>>> print mycollapsedstring.split(' ')
['collapse', 'these', 'spaces']
当没有参数传递给python的split方法时,
the documentation states
:“连续空格的运行被视为单个分隔符,如果字符串有前导或尾随空格,则结果在开始或结束处将不包含空字符串”。
抓住你的帽子,伙计们,分析一个正则表达式:
el@apollo:~/foo$ python
>>> mystring = 'zzzzzzabczzzzzzdefzzzzzzzzzghizzzzzzzzzzzz'
>>> import re
>>> mylist = re.split("[a-m]+", mystring)
>>> print mylist
['zzzzzz', 'zzzzzz', 'zzzzzzzzz', 'zzzzzzzzzzzz']
正则表达式“[a-m]+”表示小写字母。
a
通过
m
发生一次或多次的将作为分隔符匹配。
re
是要导入的库。
或者,如果您想一次一个地选择项目:
el@apollo:~/foo$ python
>>> mystring = "theres coffee in that nebula"
>>> mytuple = mystring.partition(" ")
>>> print type(mytuple)
<type 'tuple'>
>>> print mytuple
('theres', ' ', 'coffee in that nebula')
>>> print mytuple[0]
theres
>>> print mytuple[2]
coffee in that nebula
