CODEWITHSUNDEEP
pythonregex
D.C.
D.C.

Reputation: 15588

Can Regex groups and * wildcards work together?

Is there any way to combine groups and the * features of regular expressions to act kindof like a tokenizer / splitter. I tried this:

my_str = "foofoofoofoo"
pattern = "(foo)*"
result = re.search(pattern, my_str)

I was hoping my groups might look like

("foo", "foo", "foo", "foo")

But it does not. I was surprised by this because the ? and group features do work together:

my_str= "Mr foo"
pattern = "(Mr)? foo"
result = re.search(pattern, my_str)

Upvotes: 5

Views: 1816

Answers (2)

stema
stema

Reputation: 92976

The problem is you repeat your only capturing group. That means you have only one bracket ==> one capturing group, and this capturing group is overwritten each time when it matches.

See Repeating a Capturing Group vs. Capturing a Repeated Group on regular-expression.info for more information. (But capturing a repeated group is also not what you want)

So, after your regex is done, your capturing group 1 will contain the last found "foo".

This would would give you the expected result:

my_str = "foofoofoofoo"
pattern = "foo"
result = re.findall(pattern, my_str)

result is then a list ['foo', 'foo', 'foo', 'foo']

Upvotes: 4

Jon Clements
Jon Clements

Reputation: 142136

Capture groups and * don't work with the built in re module -- use findall instead.

There is a library called regex in pypi that I believe supports that syntax and has a few other features such as variable length back tracking.

Upvotes: 3

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