<Python高级全栈开发工程师-1>学习过程笔记【181-184】正则表达式 <特殊字符><函数>

>>> re.findall("juruo","iamjuruoiamnotjuruo")
[‘juruo‘, ‘juruo‘]

>>> re.findall("juruo","iamyzw")
[]

>>> re.search("ab","cdabcd")
<_sre.SRE_Match object; span=(2, 4), match=‘ab‘>
>>> re.search("ab","cdabcd").group()
‘ab‘

>>> re.search("ab+","abab")
<_sre.SRE_Match object; span=(0, 2), match=‘ab‘>

>>> re.match("abc","abcde")
<_sre.SRE_Match object; span=(0, 3), match=‘abc‘> 
>>> re.match("bcd","abcd") #匹配不成功返回空

>>> re.search("AB","12ab",re.I).group()
‘ab‘

>>> re.match("abc","ABC",re.I).group()
‘ABC‘

>>> re.findall("ab","abAB",re.I)
[‘ab‘, ‘AB‘]

>>> re.search(".","\n",re.S).group()
‘\n‘

>>> re.match("abc.","abc\n").group()
Traceback (most recent call last):
  File "<pyshell#75>", line 1, in <module>
    re.match("abc.","abc\n").group()
AttributeError: ‘NoneType‘ object has no attribute ‘group‘  （报错）
>>> re.match("abc.","abc\n",re.S).group()
‘abc\n‘

>>> re.findall(".","abc\n",re.S)
[‘a‘, ‘b‘, ‘c‘, ‘\n‘]

            rearch，match对象的方法

group(【参数】) 返回匹配的字符串

start() 返回匹配开始的位置

end() 返回匹配结束的位置

span() 返回一个元组包含匹配(开始,结束)的位置
groups() 举个栗子说明
        

>>> re.search("a","bac").group()
‘a‘
>>> re.search("a","bac").start()#左闭
1
>>> re.search("a","bac").end()  #右开
2
>>> re.search("a","bac").span() #左闭右开
(1, 2)

>>> re.match("a","abc").group()
‘a‘
>>> re.match("a","abc").start()  #左闭
0
>>> re.match("a","abc").end()    #右开
1
>>> re.match("a","abc").span()   #左闭右开
(0, 1)

>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group()  #默认为0
‘12abcABCD‘
>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(0)   #所有匹配的内容
‘12abcABCD‘
>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(1)   #返回其中第一组匹配的内容
‘12‘
>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(2)   #返回其中第二组匹配的内容
‘abc‘
>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(3)    #返回其中第三组匹配的内容
‘ABCD‘

>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(1,2)  #返回其中第一二组匹配的内容
(‘12‘, ‘abc‘)
>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(1,2,3)  #返回其中第一二三组匹配的内容
(‘12‘, ‘abc‘, ‘ABCD‘)
>>> re.search("([0-9]*)([a-z]*)([A-Z]*)","12abcABCD").group(2,3)   #返回其中第二三组匹配的内容
(‘abc‘, ‘ABCD‘)

>>> re.sub("g.t","have","I get A ,I got B, I gut C")
‘I have A ,I have B, I have C‘
>>> re.sub("g.t","have","I get A ,I got B, I gut C",1)
‘I have A ,I got B, I gut C‘
>>> re.sub("g.t","have","I get A ,I got B, I gut C",2)
‘I have A ,I have B, I gut C‘
>>> re.sub("g.t","have","I get A ,I got B, I gut C",3)
‘I have A ,I have B, I have C‘

>>> re.subn("juruo","yzw","I am juruo.My QQname is juruo,My csdn naame is juruo")
(‘I am yzw.My QQname is yzw,My csdn naame is yzw‘, 3)
>>> re.subn("juruo","yzw","I am juruo.My QQname is juruo,My csdn naame is juruo",2)
(‘I am yzw.My QQname is yzw,My csdn naame is juruo‘, 2)

>>> a=re.compile("b.c")
>>> re.findall(a,"bac")
[‘bac‘]
>>> a.findall("bac")  #也可以用生成的对象来调用finall方法，实际上a是在re上封装了这个规则..所以可以用findall
[‘bac‘]

            ‘
>>> re.split("\\d+","ab1ab2ab")
[‘ab‘, ‘ab‘, ‘ab‘]
>>> a=re.compile("\\d+")  #将正则表达式规则封装成对象a 
>>> re.split(a,"ab1ab2ab")  #使用对象a作为规则
[‘ab‘, ‘ab‘, ‘ab‘]
>>> a.split("ab1ab2ab")    #a实际上是在re中封装规则得到的，所以可以使用split
[‘ab‘, ‘ab‘, ‘ab‘]

>>> re.split("[ab]","cacbc")  
[‘c‘, ‘c‘, ‘c‘]

>>> re.findall("^123","123456")
[‘123‘]
>>> re.findall("^123","4123")
[]

>>> re.findall("456$","123456")
[‘456‘]

>>> re.findall("abc*","abc")
[‘abc‘]
>>> re.findall("abc*","abcccccc")   #贪婪匹配：它会匹配c最多的那个
[‘abcccccc‘]

>>> re.findall("ax+","axxxx")
[‘axxxx‘]

>>> re.findall("ax?","a")
[‘a‘]
>>> re.findall("ax?","ax")
[‘ax‘]
>>> re.findall("ax?","axx")
[‘ax‘]

>>> re.findall("ax{3}","axxxxxx")
[‘axxx‘]

>>> re.findall("ax{0,3}","aaxaxxaxxx")
[‘a‘, ‘ax‘, ‘axx‘, ‘axxx‘]

>>> re.search("(abc)(def)\\1","abcdefabc").group()   #这里(abc)是第1组 d(ef)是第2组
‘abcdefabc‘
>>> re.search("(abc)(def)\\2","abcdefdef").group()
‘abcdefdef‘

>>> re.search("\\bI\\b","IBIc I ").group()
‘I‘

>>> re.findall("[abcdef]haha","ahaha")
[‘ahaha‘]
>>> re.findall("[abcdef]haha","abhaha")
[‘bhaha‘]

>>> re.findall("a[.]b","aab")
[] #没有起到通配符的作用
>>> re.findall("a[.]b","a.b")  #和.匹配
[‘a.b‘]

>>> re.findall("[a-z]","abcdefg")#一个一个字符遍历"abcdefg"进行匹配
[‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘, ‘g‘] 

            >>> re.findall("[0-9]","0123456789") 
[‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘]
        

>>> re.findall("[^1-9]","12345abc")
[‘a‘, ‘b‘, ‘c‘]

>>> re.search("a\d+","a23b")
<_sre.SRE_Match object; span=(0, 3), match=‘a23‘>
>>> re.search("a\d+","a23b").group()
‘a23‘
>>> re.search("a\d+","a2312345").group()
‘a2312345‘

>>> re.search("a\d+?","a2312345").group()
‘a2‘
>>> re.search("a\d*?","a2312345").group()
‘a‘

>>> re.search("a(\d+?)b","a23b").group()
‘a23b‘