Python - Regex 之 findall

谨记：我只提取我需要的字符串，其它的扔掉。扫描方向 从左至右

正则 re.findall  的简单用法（返回string中所有与pattern相匹配的全部字串，返回形式为数组）

>>> regular_v1 = re.findall(r"docs","https://docs.python.org/3/whatsnew/3.6.html")
>>> print (regular_v1)
['docs']
>>> regular_v2 = re.findall(r"^https","https://docs.python.org/3/whatsnew/3.6.html")
>>> print (regular_v2)
['https']

用$符号表示以html结尾的字符串返回,判断是否字符串结束的字符串

>>> regular_v3 = re.findall(r"html$","https://docs.python.org/3/whatsnew/3.6.html")
>>> print (regular_v3)
['html']

>>> regular_v5 = re.findall(r"\d","https://docs.python.org/3/whatsnew/3.6.html")
>>> print (regular_v5)
['3', '3', '6']
>>> regular_v6 = re.findall(r"\d\d\d","https://docs.python.org/3/whatsnew/3.6.html/1234")
>>> print (regular_v6)
['123']

“W”在正则里面代表匹配除了字母与数字以外的特殊符号

>>> regular_v9 = re.findall(r"\W","https://docs.python.org/3/whatsnew/3.6.html")
>>> print (regular_v9)
[':', '/', '/', '.', '.', '/', '/', '/', '.', '.']

注意：与 search group 区别：

>>> s1 = 'Hello, this is Joey'
>>> s2 = 'The first price is $9.90 and the second price is $100'
>>> print(re.findall(r'\w+', s1))
['Hello', 'this', 'is', 'Joey']
>>> print(re.findall(r'\d+', s2))
['9', '90', '100']
>>> s2 = 'The first price is $9.90 and the second price is $100'
>>> print(re.search(r'\d+', s2).group())
9
>>> for m in re.finditer(r'\d+', s2):
        print(m.group())  
9
90
100

。