Does no one use index() anymore?!? 

#!/usr/bin/perl

use warnings; use strict;

sub find_nth {
   my ($s,$c,$n) = @_;
   my $pos = -1;
   while ($n--) {
      $pos = index($s,$c,$pos+1);
      return -1 if $pos == -1;
   }
   return $pos;
}

my $str="Now is the time for all good men to come to the aid of their 
+country";
my $n = 5;
my $c = "o";

print find_nth($str,$c,$n), "\n";

[download]

I'll leave it to those people who like to benchmark to decide whether or not this is an "efficient Perl function" :-)

duff

In reply to Re: The nth occurrence of a character by duff
in thread The nth occurrence of a character by Anonymous Monk

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.