You can try using the e modifier in the substitution and have the replacement be something like this:

/qq{<$1 $2="$3,$5"} . ($4 || '')/gex

This should remove the warning by using '' instead of $4 if it's empty (it can't be 0 so there is no need for defined $4 here).

--
The Error Message is GOD - MJD

In reply to Re: Using undefined back-references? by mirod
in thread Using undefined back-references? by tommyw

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