目錄python
1、re.findall函數介紹正則表達式
2、代碼以下數組
它在re.py中有定義:this
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)
返回string中全部與pattern匹配的所有字符串,返回形式爲數組。spa
後面會講解代碼裏的各個部分,先列出來~code
import re str = 'aabbabaabbaa' #一個"."就是匹配除 \n (換行符)之外的任意一個字符 print(re.findall(r'a.b',str))#['aab', 'aab'] #*前面的字符出現0次或以上 print(re.findall(r'a*b',str))#['aab', 'b', 'ab', 'aab', 'b'] #貪婪,匹配從.*前面爲開始到後面爲結束的全部內容 print(re.findall(r'a.*b',str))#['aabbabaabb'] #非貪婪,遇到開始和結束就進行截取,所以截取屢次符合的結果,中間沒有字符也會被截取 print(re.findall(r'a.*?b',str))#['aab', 'ab', 'aab'] #非貪婪,與上面同樣,只是與上面的相比多了一個括號,只保留括號的內容 print(re.findall(r'a(.*?)b',str))#['a', '', 'a'] str = '''aabbab aabbaa bb'''#後面多加了2個b #沒有把最後一個換行的aab算進來 print(re.findall(r'a.*?b',str))#['aab', 'ab', 'aab'] #re.S不會對\n進行中斷 print(re.findall(r'a.*?b',str,re.S))#['aab', 'ab', 'aab', 'aa\n b']
字符串是字符串
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']