In [1]: import time

In [2]: import datetime

In [3]: date_time = datetime.datetime.now()

In [4]: print(date_time)
2016-11-17 16:36:57.580709

In [6]: current_date = str(date_time).split(" ")

In [7]: print current_date
[‘2016-11-17‘, ‘16:36:57.580709‘]

In [8]: current_date = str(date_time).split(" ")[0]

In [9]: print current_date                         
2016-11-17

In [22]: a = re.findall("ab","cavvvvvv")  #将匹配到的字符添加至列表中，因为没匹配到，所以列表为空

In [23]: a
Out[23]: []

In [24]: a = re.findall("ab","cabvvvvv") #匹配到了ab,所以列表元素为ab

In [25]: a
Out[25]: [‘ab‘]

In [26]: a = re.split("ab","cabvvvvv")  #将匹配到的字符作为分隔符

In [27]: a
Out[27]: [‘c‘, ‘vvvvv‘]

In [29]: a = re.sub("ab","ed","cabvvvvv") #将匹配到的字符用ed替换

In [30]: a
Out[30]: ‘cedvvvvv‘

‘.‘     默认匹配除\n之外的任意一个字符，若指定flag DOTALL,则匹配任意字符，包括换行
‘^‘     匹配字符开头，若指定flags MULTILINE,这种也可以匹配上(r"^a","\nabc\neee",flags=re.MULTILINE)
‘$‘     匹配字符结尾，或e.search("foo$","bfoo\nsdfsf",flags=re.MULTILINE).group()也可以
‘*‘     匹配*号前的字符0次或多次，re.findall("ab*","cabb3abcbbac")  结果为[‘abb‘, ‘ab‘, ‘a‘]
‘+‘     匹配前一个字符1次或多次，re.findall("ab+","ab+cd+abb+bba") 结果[‘ab‘, ‘abb‘]
‘?‘     匹配前一个字符1次或0次
‘{m}‘   匹配前一个字符m次
‘{n,m}‘ 匹配前一个字符n到m次，re.findall("ab{1,3}","abb abc abbcbbb") 结果‘abb‘, ‘ab‘, ‘abb‘]
‘|‘     匹配|左或|右的字符，re.search("abc|ABC","ABCBabcCD").group() 结果‘ABC‘
‘(...)‘ 分组匹配，re.search("(abc){2}a(123|456)c", "abcabca456c").group() 结果 abcabca456c
 
 
‘\A‘    只从字符开头匹配，re.search("\Aabc","alexabc") 是匹配不到的
‘\Z‘    匹配字符结尾，同$
‘\d‘    匹配数字0-9
‘\D‘    匹配非数字
‘\w‘    匹配[A-Za-z0-9]
‘\W‘    匹配非[A-Za-z0-9]
‘s‘     匹配空白字符、\t、\n、\r , re.search("\s+","ab\tc1\n3").group() 结果 ‘\t‘
 
‘(?P<name>...)‘ 分组匹配 re.search("(?P<province>[0-9]{4})(?P<city>[0-9]{2})(?P<birthday>[0-9]{4})","371481199306143242").groupdict("city") 结果{‘province‘: ‘3714‘, ‘city‘: ‘81‘, ‘birthday‘: ‘1993‘}