Python RE庫的貪婪匹配和最小匹配

>>> import re
>>> match = re.search(r'PY.*N', 'PYANBNCNDN')
>>> match.group(0)
'PYANBNCNDN'
>>>

其中滿足條件的有：

1. PYAN
2. PYANBN
3. PYANBNCN
4. PYANBNCNDN

結果輸出了一個最長的：PYANBNCNDN

叫做：貪婪匹配！

>>> import re
>>> match = re.search(r'PY.*N', 'PYANBNCNDN')
>>> match.group(0)
'PYANBNCNDN'
>>> match = re.search(r'PY.*N', 'PYANBNCND')
>>> match.group(0)
'PYANBNCN'
>>> match = re.search(r'PY.*N', 'PYABNCND')
>>> match.group(0)
'PYABNCN'
>>> match = re.search(r'PY.*N', 'PYABHDHDH')
>>>

最上面的那一個就是沒有滿足條件的！

那麼，如何輸出最小的匹配呢？

match = re.search(r'PY.*?N', 'PYANBNCNDN')

>>> import re
>>> m = re.search(r'PY.*N', 'PYDFSNDFNJNCNIS')
>>> m.group(0)
'PYDFSNDFNJNCN'
>>> m = re.search(r'PY.*?N', 'PYDFSNDFNJNCNIS')
>>> m.group(0)
'PYDFSN'
>>>

課程地址：https://www.icourse163.org/learn/BIT-1001870001?tid=1003245012#/learn/content?type=detail&id=1004574448&cid=1005754054