Overlapping Matches With Finditer() In Python
I'm using a regex to match Bible verse references in a text. The current regex is REF_REGEX = re.compile(''' (?
Solution 1:
A character consumed is consumed, you should not ask the regex engine to go back.
From your examples the verse part (e.g. :1) seems not optional. Removing that will match the last bit.
ref_regex = re.compile('''
(?<!\w) # Not preceeded by any words((?i)q(?:uote)?\s+)? # Match 'q' or 'quote' followed by many spaces
(
(?:(?:[1-3]|I{1,3})\s*)? # Match an arabic or roman number between 1 and 3.
[A-Za-z]+ # Match many alphabetics
)\.? # Followed by an optional dot(?:
\s*(\d+) # Match the chapter number
(?:
[:.](\d+) # Match the verse number
(?:-(\d+))? # Match the ending verse number
) # <-- no '?' here
)
(?:
\s+
(?:
(?i)(?:from\s+)| # Match the keyword 'from' or 'in'
(?:in\s+)|
(?P<lbrace>\() # or stuff between (...)
)\s*(\w+)
(?(lbrace)\))
)?
''', re.X | re.U)
(If you're going to write a gigantic RegEx like this, please use the /x flag.)
If you really need overlapping matches, you could use a lookahead. A simple example is
>>> rx = re.compile('(.)(?=(.))')
>>> x = rx.finditer("abcdefgh")
>>> [y.groups() for y in x]
[('a', 'b'), ('b', 'c'), ('c', 'd'), ('d', 'e'), ('e', 'f'), ('f', 'g'), ('g', 'h')]
You may extend this idea to your RegEx.
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