Your captures will always be numbered according to the leftmost opening parenthesis, for instance: 

  'abcdef' =~ / ( abc ( def) ) /x;
   $1 -> 'abcdef'
   $2 -> 'def'

[download]

So you have two options here. You can either specify each matching group, or match in a loop. For instance:

    use Data::Dumper;
    my $table_ref="!Frequency[A][B][C]  ..some other text..";


    ### Groups specified explicitly

    my $var_rx   = qr / \[ ( [^\]]+ ) \] /x;
    my $file_rx  = qr / ! ( [^\[]+ ) /x;
    my $regex    = qr/^ $file_rx $var_rx $var_rx? $var_rx? $var_rx? \s
++.*/x;
 
    my @matches  = ( $table_ref =~ /$regex/);
    print Dumper (\@matches);    

    ## Loop
    my ($filename) = ($table_ref =~ /^ $file_rx /gcx );

    my @vars;
    while ( $table_ref =~ /\G $var_rx/gcx ) {
        push @vars,$1;
    }

    print Dumper($filename,\@vars);

[download]

See perlre for an explanation of \G and /c

clint

In reply to Re: Regex - backreferencing multiple matches in one group. by clinton
in thread Regex - backreferencing multiple matches in one group. by why_bird

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.