$data =~ /tag2=(\d+)/;
$tag2 = $1 if $1;
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I am afraid this will not work correctly if the regex fails, because $1 will still be set to its previous value (previous regex match). So that rather than testing $1, we should test whether the regex matched.

I think that you would need rather something like this:

$tag1 = $1 if $data =~ /tag1=(\d+)/;
$tag2 = $1 if $data =~ /tag2=(\d+)/;
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