CODEWITHSUNDEEP
rubyregexstringlookbehindnegative-lookbehind
tybro0103
tybro0103

Reputation: 49693

Regex negative lookbehind in Ruby doesn't seem to work

Making an argument parser. I want to split a string into an array where the delimiter is ", " except when preceded by "|". That means string

"foo, ba|, r, arg"

should result in

`["foo", "ba|, r", "arg"]`

I'm trying to use this regex: (?<!\|), which works in http://regexhero.net/tester/ but when I try

args.split(/(?<!\|), /)

in ruby, I get an error: undefined (?...) sequence: /(?<!\|), /

Upvotes: 6

Views: 2648

Answers (1)

NullUserException
NullUserException

Reputation: 85458

Ruby's regex engine doesn't support lookbehind (yet).

You'd need to switch to 1.9 or use Oniguruma.

If that's not an option, you can search for |, and replace it with some sort of marker. After all is said and done, put the |, back.

You can also try a regex like:

/(?:[^|]), /

But obviously the (?:[^|]) is not zero-width, which means you'll need to do some extra work afterwards.

Upvotes: 10

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