Is there a Perl shortcut to count the number of matches in a string?

arrays regex perl perl4
Geo picture Geo · Dec 4, 2009 · Viewed 60.3k times · Source

Suppose I have:

my $string = "one.two.three.four";

How should I play with context to get the number of times the pattern found a match (3)? Can this be done using a one-liner?

I tried this:

my ($number) = scalar($string=~/\./gi);

I thought that by putting parentheses around $number, I'd force array context, and by the use of scalar, I'd get the count. However, all I get is 1.

Answer

friedo picture friedo · Dec 4, 2009

That puts the regex itself in scalar context, which isn't what you want. Instead, put the regex in list context (to get the number of matches) and put that into scalar context.

 my $number = () = $string =~ /\./gi;

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