Menu
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?
483
Capturing groups are a way to treat multiple characters as a single unit. They are created by placing the characters to be grouped inside a set of parentheses. For example, the regular expression (dog) creates a single group containing the letters "d", "o", and "g".
Capturing groups are a handy feature of regular expression matching that allows us to query the Match object to find out the part of the string that matched against a particular part of the regular expression. Anything you have in parentheses () will be a capture group.
groups() method. This method returns a tuple containing all the subgroups of the match, from 1 up to however many groups are in the pattern.
In regular expressions, the period ( . , also called "dot") is the wildcard pattern which matches any single character. Combined with the asterisk operator . * it will match any number of any characters.
re.findall(r"\w","abcdefg") 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.
29
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
