Regex match required and optional parts of string

Question

I'd like to do a preg_match on a uri string with optional and required parts but I can't figure it out.

Example to match:

/segment/(required)/segment(/optional)

I want both strings below to match against the above

/segment/required/segment/optional

and

/segment/reguired/segment

I know the policy is to not write for me but I can't figure this out so thought I'd at least ask.

Answer 1

The question mark makes the preceding token in the regular expression optional. E.g.: colou?r matches both colour and color.

You can make several tokens optional by grouping them together using round brackets, and placing the question mark after the closing bracket. E.g.: Nov(ember)? will match Nov and November.

You can write a regular expression that matches many alternatives by including more than one question mark. Feb(ruary)? 23(rd)? matches February 23rd, February 23, Feb 23rd and Feb 23.

Source: http://www.regular-expressions.info/optional.html