SPUG: Counting the number of instances in a string using Perl's regexes...

[Jonathan Gardner]

Say I had a string with a whole bunch of characters - "asdfjkhafjklhaf".

How would I go about counting the number of individual characters (say,
'a')?

One way I found in the book is this:
@arr = $string =~ m/a/g;
$number_of_a = scalar @arr;

Is there a more elegant way of going about this? I want to skip the creation
of @arr (I am worried about performance. The actual thing I will match is a
little big and will take some time to write to an array.) I have a gut
feeling that there is, and I just don't know what it is yet...

BTW, it's not:
$number = scalar $string =~ m/a/g;
or
$number = scalar ($string =~ m/a/g);

This use of scalar forces the function (m//) to return a scalar not an
array. It doesn't take the array we want so badly and count the number of
elements.

Jonathan M. Gardner
CarDomain Networks
(425)820-2244 x23
gardner at sounddomain.com


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