CODEWITHSUNDEEP
regex
DanTdd
DanTdd

Reputation: 342

How to not include leading whitespace in multiple optional capture grouped regex

I have a regex with multiple optional capture groups.

notify (?<action>[^\s]+)(?:(?<query>(?:(?! by ).)*))(?: by (?<id>\w+))?

The strings I am using to match are:

notify enable
notify disable
notify add hello
notify remove hello how are you
notify add 983734987 by id
notify remove hello by id
notify add hello by name
notify remove hello by name

As you can see, action will either be enable, disable, add, or remove. query SHOULD be either empty, hello, hello how are you or 983734987 but it always picks up a leading whitespace, id will either be empty, id or name.

I can do more simple regex but when it looks like this I find it hard to understand. I have tried putting a ^\s near query so it doesn't have the leading whitespace but can't seem to get it to work.

So I need the query capture group to ditch the leading whitespace it's picking up. Any help would be great.

Upvotes: 1

Views: 23

Answers (1)

CertainPerformance
CertainPerformance

Reputation: 370809

I would put everything after action into an optional group, and use lazy repetition for the query rather than (greedy repetition combined with negative lookahead), I think it's a bit more readable.

Careful of \s because it can match newlines, which probably isn't desirable here. Rather than [^\s]+, you can use \S+. (\S is the negation of \s)

^notify (?<action>\S+)(?: +(?<query>.+?)(?: by (?<id>\w+))?)?$

https://regex101.com/r/xdM3I8/2

Upvotes: 1

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