This is a good use for the /e option on the substitution operator.

use strict;
use warnings;

$_ = <DATA>;

if (/<figr n="/) {
  s[<figr n="(\d+)">(.*?)</figr>]
   [qq(<FIGIND NUM="$1" ID="FG.) . sprintf('%03d', $1) . qq(">$2</FIGI
+ND>)]eg;
}

print;

__DATA__
Nerve cells come in many shapes and sizes, but they all have a number 
+of identifiable parts. A typical nerve cell is shown in <figr n="1">F
+igure 1</figr>. Like all other cells in the body, it has a nucleus th
+at contains genetic information.<figr n="2">Figure 2</figr>. The cell
+ is covered by a membrane and is filled with a fluid.

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<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

In reply to Re: Matching a pattern in Regex by davorg
in thread Matching a pattern in Regex by rsriram

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