Match string that ends with a given substring, except for certain cases, in Rails

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.

Answer 2

我不是“正则专家”，所以我确定可能有更好的方法，但是我想出了

/(.+[^associated_id].+)_id$/