'''
r:Python中字符串前面加上 r 表示原生字符串(rawstring)
不使用r,那么匹配时候需要4个反斜杠,正则需要转化一次,python解释器需要转化一次
'''
mm="c:\ab\bc\cd\"
print (mm)
r=re.match("c:\\ab",mm)
print (r.group())
r=re.match(r"c:\ab",mm).group()
print (r)
-----------------------------------
c:abccd
c:a
c:a
----------------------------------------------------------------------------------------------------------------------------
>>> re.findall("abc","adsssa abc ")
[]
>>> re.findall(r"abc","adsssa abc ")
['abc']
>>> re.findall(r"abc","adsssa abc*")
['abc']
>>> re.findall(r"I","I LOVE IOU")
['I']
>>> re.findall(r"I","IMISS IOU")
[]
>>> re.findall(r"I","IMISS IOU")
['I', 'I']