in reply to Re: Highlight a substring
in thread Highlight a substring

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";

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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.

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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;

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