Match regex and assign results in single line of code

Question

I want to be able to do a regex match on a variable and assign the results to the variable itself. What is the best way to do it?

I want to essentially combine lines 2 a

Answer 1

Also, to amplify the accepted answer using the ternary operator to allow you to specify a default if there is no match:

my $match = $variable =~ /(*pattern*).*/ ? $1 : *defaultValue*;

Answer 2

my($variable) = "some string" =~ /(e\s*str)/;

This works because

If the /g option is not used, m// in list context returns a list consisting of the subexpressions matched by the parentheses in the pattern, i.e., ($1, $2, $3 …).

and because my($variable) = ... (note the parentheses around the scalar) supplies list context to the match.

If the pattern fails to match, $variable gets the undefined value.

Answer 3

You can do substitution as:

$a = 'stackoverflow';
$a =~ s/(\w+)overflow/$1/;

$a is now "stack"

Answer 4

$variable2 = "stackoverflow";
(my $variable1) = ($variable2 =~ /stack(\w+)/);

$variable1 now equals "overflow".

Answer 5

Almost ....

You can combine the match and retrieve the matched value with a substitution.

$variable =~ s/.*(find something).*/$1/;

AFAIK, You will always have to copy the value though, unless you do not care to clobber the original.

Answer 6

I do this:

#!/usr/bin/perl

$target = "n: 123";
my ($target) = $target =~ /n:\s*(\d+)/g;
print $target; # the var $target now is "123"