CODEWITHSUNDEEP
pythonregexregex-group
Frayt
Frayt

Reputation: 1223

Non capturing groups within named groups

I want to match one of a collection of strings with a prefix or suffix e.g.

the color is red red is the color

I want to match groups color: red

So my first attempt was the obvious

(?<color>(?:the color is )(red|green|blue)|(red|green|blue)(?: is the color))

I was expecting this to match one group color: red but it matches color: the color is red, 2: red

I have also tried with the (?>) atomic operator

I tried moving the prefix / suffix groups outside of the named group:

(?:the color is )(?<color>red|green|blue)(?: is the color)

But this will only match strings with the prefix and suffix e.g. the color is red is the color. Maybe I could use the lookahead or lookbehind operators with this?

I cannot use the (?J) modifier as the regex engine I am using (python re module does not support this.

Upvotes: 1

Views: 101

Answers (1)

Serge Ballesta
Serge Ballesta

Reputation: 148870

I could not manage to use non capturing groups inside named groups, but at least this correctly extracts red as group('color'):

m = re.search(r"(?P<color>((red|green|blue)(?= is the color)|(?<=the color is )(red|green|blue)))", t)

Upvotes: 1

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