Question

I have a regex /(.+)_id$/ in a rails application that matches any string that ends with _id . I need it to match any string that ends with _id except associated_id. How can I accomplish this?

thx 🙂

-C

Answer 1

/(.+)(?<!associated)_id$/

will use negative lookbehind to make sure that whatever was matched by (.+) doesn’t end in associated.

For languages that don’t support lookbehind, you can use this:

/\A(?!.*associated_id$)(.+)_id$/

This will assert that it’s not possible to match a string ending in associated_id from the starting position of the string.