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I have a Python regular expression that contains a group which can occur zero or many times - but when I retrieve the list of groups afterwards, only the last one is present. Example:

re.search("(\w)*", "abcdefg").groups()

this returns the list ('g',)

I need it to return ('a','b','c','d','e','f','g',)

Is that possible? How can I do it?

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2 Answers 2

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re.findall(r"\w","abcdefg")
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+1: You can't do it with a single regex capture; you have to do it another way.
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In addition to Douglas Leeder's solution, here is the explanation:

In regular expressions the group count is fixed. Placing a quantifier behind a group does not increase group count (imagine all other group indexes increment because an eralier group matched more than once).

Groups with quantifiers are the way of making a complex sub-expression atomic, when there is need to match it more than once. The regex engine has no other way than saving the last match only to the group. In short: There is no way to achieve what you want with a single "unarmed" regular expression, and you have to find another way.

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2 Comments

As an addition: Modern regex implementations like the one in .NET allow you to access previous occurrences of a group besides the last one. Therefore, the above statement is not univerally true, but still holds for the most implementations.
For the record, there's a regex implementation for Python which also permits access to all of the matches of a capture group: pypi.python.org/pypi/regex

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