Re: mysteries of regex substring matching

> So, is there a way to use capture groups to match multiple times like separate groups does in the first example?

It depends what your goal is.

If it's simply using a quantifier {4} the answer is no, because only the last match will be kept for the unique first group , that's why you get 01D9 at the end. Not a mystery.

But there are numerous workarounds I can think of.

using the /g modifier in a loop /(....)/g
reading the last capture with embedded Perl code like /(....(?{print $1})){4}/

updates

minor corrections
links to perlretut

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^2: mysteries of regex substring matching by LanX (Saint) on Jan 15, 2021 at 22:45 UTC
> using the /g modifier in a loop /(....)/g demo: `DB<53> $x = q[AAD34017837201D98AAED18778DEF993]; DB<54> $x =~ m/(....)/g and say $1 for 1..4 AAD3 4017 8372 01D9 DB<55>` [download] Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l]
Re^2: mysteries of regex substring matching by LanX (Saint) on Jan 15, 2021 at 22:53 UTC
> reading the last capture with embedded Perl code like `/(....(?{print $1})){4}/` demo: (using /x for clarification) `DB<66> $x = q[AAD34017837201D98AAED18778DEF993]; DB<67> $x =~ m/(?: (....) (?{say $1}) ) {4} /x AAD3 4017 8372 01D9 DB<68>` [download] update I think this explains your "mystery", they all match but only the last one is kept in $1. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l] [select]