> If you would like to use a regex as a variable, you should use qr.

Not always. There are some advantages to using qr. There are some disadvantages as well. 1) qr takes more memory than a string, which may matter if you have a lot of them. 2) in some cases, if you construct a large regex out of many small parts, qr is significantly slower than using strings - this is because in non-trivial interpolations, a qr-ed regex first gets stringified, which gives lots of extra parenthesis. 

#!perl -w
use Devel::Size 'size';

print size('Price: \$([0-9]+\.[0-9]+)'), "\n";
print size(qr/Price: \$([0-9]+\.[0-9]+)/), "\n";
__END__
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In reply to Re^2: Perl & Regex by Anonymous Monk
in thread Perl & Regex by Kzin

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