Python的正則表達式：僅獲得一個表達式匹配

Question

所以我有一個程序，對一個說法匹配多個正則表達式摔跤：

import re 

line = "Remind me to pick coffee up at Autostrada at 4:00 PM" 

matchObj = re.match(r'Remind me to (.*) at (.*?) at (.*?) .*', line, re.M|re.I|re.M) 
matchObj2 = re.match(r'Remind me to (.*) at (.*?) .*', line, re.M|re.I) 

if matchObj: 
    print("matchObj.group() : ", matchObj.group()) 
    print("matchObj.group(1) : ", matchObj.group(1)) 
    print("matchObj.group(2) : ", matchObj.group(2)) 
    print("matchObj.group(3) :", matchObj.group(3)) 
else: 
    print("No match!!") 
if matchObj2: 
    print("matchObj2.group() : ", matchObj2.group()) 
    print("matchObj2.group(1) : ", matchObj2.group(1)) 
    print("matchObj2.group(2) : ", matchObj2.group(2)) 
else: 
    print("No match!!") 

現在，我只想要一個正則表達式匹配的時間，像這樣的：

matchObj.group() : Remind me to pick coffee up at Autostrada at 4:00 PM 
matchObj.group(1) : pick coffee up 
matchObj.group(2) : Autostrada 
matchObj.group(3) : 4:00 

相反，無論是正則表達式匹配的聲明，就像這樣：

matchObj.group() : Remind me to pick coffee up at Autostrada at 4:00 PM 
matchObj.group(1) : pick coffee up 
matchObj.group(2) : Autostrada 
matchObj.group(3) : 4:00 
matchObj2.group() : Remind me to pick coffee up at Autostrada at 4:00 PM 
matchObj2.group(1) : pick coffee up at Autostrada 
matchObj2.group(2) : 4:00 

這裏只有matchObj應該是一個合適的比賽，那麼如何阻止其他正則表達式報告比賽？

Answer 1

的問題是，每個字符串匹配的第一個正則表達式也匹配第二個（匹配at (.*?) .*也符合.*什麼。所以matchObj2 是實際上是一個正確的比賽。

如果要區分這兩種的情況下，你需要當且僅當第一個沒有匹配的應用第二正則表達式。

import re 

line = "Remind me to pick coffee up at Autostrada at 4:00 PM" 

matchObj = re.match(r'Remind me to (.*) at (.*?) at (.*?) .*', line, re.M|re.I|re.M) 
matchObj2 = re.match(r'Remind me to (.*) at (.*?) .*', line, re.M|re.I) 

if matchObj: 
    print("matchObj.group() : ", matchObj.group()) 
    print("matchObj.group(1) : ", matchObj.group(1)) 
    print("matchObj.group(2) : ", matchObj.group(2)) 
    print("matchObj.group(3) :", matchObj.group(3)) 
elif matchObj2: 
    print("matchObj2.group() : ", matchObj2.group()) 
    print("matchObj2.group(1) : ", matchObj2.group(1)) 
    print("matchObj2.group(2) : ", matchObj2.group(2)) 
else: 
    print("No match!!")