Python re.findall中正则表达式(.*?)和参数re.S使用_python_

def findall(pattern, string, flags=0): """Return a list of all non-overlapping matches in the string. If one or more capturing groups are present in the pattern, return a list of groups; this will be a list of tuples if the pattern has more than one group. Empty matches are included in the result.""" return _compile(pattern, flags).findall(string) 

import re str = 'aabbabaabbaa' #一个"."就是匹配除 \n (换行符)以外的任意一个字符 print(re.findall(r'a.b',str))#['aab', 'aab'] #*前面的字符出现0次或以上 print(re.findall(r'a*b',str))#['aab', 'b', 'ab', 'aab', 'b'] #贪婪，匹配从.*前面为开始到后面为结束的所有内容 print(re.findall(r'a.*b',str))#['aabbabaabb'] #非贪婪，遇到开始和结束就进行截取，因此截取多次符合的结果，中间没有字符也会被截取 print(re.findall(r'a.*?b',str))#['aab', 'ab', 'aab'] #非贪婪，与上面一样，只是与上面的相比多了一个括号，只保留括号的内容 print(re.findall(r'a(.*?)b',str))#['a', '', 'a'] str = '''aabbab aabbaa bb'''#后面多加了2个b #没有把最后一个换行的aab算进来 print(re.findall(r'a.*?b',str))#['aab', 'ab', 'aab'] #re.S不会对\n进行中断 print(re.findall(r'a.*?b',str,re.S))#['aab', 'ab', 'aab', 'aa\n b'] 

str = 'aabbabaabbaa' 

print(re.findall(r'a.b',str)) ['aab', 'aab'] 

print(re.findall(r'a*b',str)) ['aab', 'b', 'ab', 'aab', 'b'] 

print(re.findall(r'a.*b',str)) ['aabbabaabb'] 

print(re.findall(r'a.*?b',str)) ['aab', 'ab', 'aab'] 

print(re.findall(r'a(.*?)b',str)) ['a', '', 'a'] 

str = '''aabbab aabbaa bb''' 

print(re.findall(r'a.*?b',str)) ['aab', 'ab', 'aab'] 

print(re.findall(r'a.*?b',str,re.S)) ['aab', 'ab', 'aab', 'aa\n b']