pattern matching help 1

[Graziella]

Hi,

I have a list of patterns, for instance,
$pattern = "l\,?454\s*\-?\s*f(oo|ee)t";

The usual way of looking for that pattern in a string, that is,
if ($test =~ /$pattern/){ #do something }
does not work.
How could I tell perl that $pattern is an already formed regular expression ?

Thank you for any help.

Grazia

 

[tweenerz]

Your original test works fine (I tested it). Try it with an easier regex and work your way up until you find whats causing it to not match.

The problem lies in your regex, not the interpolation of the variable.

 

[mikevh]

Check out qr//.
$pattern = qr/l,?454\s*-?\s*f(oo|ee)t/;

I removed the \ before the comma and before the -. Commma is never special and - is special only in char classes, when not the first or last character.

As an alternative, you could just put the expression in single quotes (''). If you use double quotes, ("") you need 2 backslashes to equal a single backslash.

HTH

 

[Graziella]

Hi Mikevh,

may I ask you why "qr".
Maybe you meant "qw"

Grazia

 

[ishnid]

qr// complies a string into a regexp. qw// produces a list of words from a space-seperated collection of words.

You can read more on them in perlop, under `regexp quote-like operators'.