Regex Optional Groups?

Question

I seem to have confused myself with a preg_match regex I\'m doing, so fresh eyes and help would be appreciated.

My current regex is as follows:

/<         


        

Answer 1

Like this:

/<!--menu:start(?::\((\d),(\d)\))?-->(.*?)<!--menu:end-->/se

I've added a non-capturing group, (?: ), around the part you want to be optional, and then suffixed it with a question mark: (?:<optional content>)?

Answer 2

This uses an optional non-capturing group -- (?: )? -- to match your optional part, and also \d instead of [0-9] to match digits:

/<!--menu:start(?::\((\d),(\d)\))?-->(.*?)<!--menu:end-->/se

If numbers in parentheses can consist of more than one digit, use this one instead:

/<!--menu:start(?::\((\d+),(\d+)\))?-->(.*?)<!--menu:end-->/se

Answer 3

Enclose with a non matching group and set it to optional : (?:...)?

/<!--menu:start(?::\(([0-9])\,([0-9])\))?-->(.*?)<!--menu:end-->/se