Employing a little regex look ahead trickery gives something like this:

use strict;
use warnings;

my $pat = 'ono';
my $str = <<STR;
ono is the pattern to match. ono is found once in onono
STR
#123456789012345678901234567890123456789012345678901234
#         1         2         3         4         5    

for my $count (1..4) {
    if ($str =~ /(?:(?:(?!$pat).)*($pat)){$count}/) {
        print "Match at $-[1] for count = $count\n";
    } else {
        print "No match for count = $count\n";
    }
}

[download]

Prints:

Match at 0 for count = 1
Match at 29 for count = 2
Match at 50 for count = 3
No match for count = 4

[download]

Note that at least simple regex matches are fine in the pattern including look ahead and look back matches, but avoid capture groups.

DWIM is Perl's answer to Gödel

In reply to Re: search for nth occurrence of a pattern in a line by GrandFather
in thread search for nth occurrence of a pattern in a line by deepa

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.