How can I make part of a Perl regular expression optional?

Question

I want match

 my @array = ( 'Tree' , 'JoeTree');

    foreach (@array ) {
      if ( $_ =~ /^(Joe)Tree/gi) {
        print "matched $_";
      }
    }

It matching only JoeTree. It's not matching Tree ?

Answer 1

You missed a ?: /^(Joe)?Tree/gi

Answer 2

Try:

if (/^(?:Joe)?Tree/gi)

• We've made the Joe part optional.
• Also you can change (..) to (?:...) as you are just grouping.
• Also $_ =~ part is redundant as by default we check in $_