Re: Highlight a substring

see: index and substr

my $string1 = 'realy long string of html';
my $string2 = 'long';
my $index = index($string1, $string2);
while($index > 0){
   substr($string1, $index, length($string2), '<b>'.$string2.'</b>');
   $index = index($string1, $string2, ($index + length($string2)));
}
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Comment on Re: Highlight a substring Download Code

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Re^2: Highlight a substring by ikegami (Patriarch) on Apr 06, 2005 at 15:23 UTC
That should be `while ($index >= 0) {` and not `while ($index > 0) {`	[reply] [d/l] [select]
Re^2: Highlight a substring by the_0ne (Pilgrim) on Apr 06, 2005 at 17:02 UTC
I have more of a question than a comment. The first thing I would have thought to do was this... `my $string1 = 'realy long string of html and here is the word long aga +in'; my $string2 = 'long'; + $string1 =~ s/($string2)/<b>$1<\/b>/g; + print "string1: $string1\n";` [download] I know tmtowtdi, but is there another reason that the 2 responses to MonkPaul's question didn't involve s///g? Thanks again oh wise monks.	[reply] [d/l]
Re^3: Highlight a substring by ikegami (Patriarch) on Apr 06, 2005 at 18:09 UTC
`index` is much faster than `m//` when matching a constant string. I'm guessing `index` + `substr` is similarly faster than `s///`. Feel free to benchmark the two. By the way, `$string1 =~ s/($string2)/<b>$1<\/b>/g;` should be replaced with `$string1 =~ s/(\Q$string2\E)/<b>$1<\/b>/g;` in case $string2 contains special characters. Better yet, `$string1 =~ s/((?:\Q$string2\E)+)/<b>$1<\/b>/g;` should be a little bit faster. I'd also Benchmark the following which has fewer concatenations: `$string1 =~ s#(?=(?:\Q$string2\E)+)#<b>#g; $string1 =~ s#(?<=(?:\Q$string2\E)+)#</b>#g;` [download]	[reply] [d/l] [select]