NYCPHP Meetup

[Dan Cech]

Ophir Prusak wrote:
> Woops - I read your code to fast :)
> I didn't see you were doing this for multiple key words.
> 
> In any case though it would be good to use the \b word boundry
> modifier so you won't be highlighting substring word matches.

The word boundary modifier is a good idea if that's what you want, but 
be careful about constructing preg strings without using preg_quote, you 
can get into real trouble if the user enters something odd.

The syntax should be:

function highlight($keyword, $text) {
   return preg_replace('/\b'. preg_quote($keyword,'/') 
.'\b/i','<b>$0</b>',$text);
}

Note that the character used to delimit the preg expression (in this 
case /) is passed as the second parameter to preg_quote.

I'm not sure exactly why but the PHP manual indicates that $0 is the 
preferred form for backreferences in the replacement string since 4.04.

 From http://php.net/preg_replace

> Replacement may contain references of the form \\n or (since PHP 4.0.4) $n, with the latter form being the preferred one.

Dan

> On Tue, 19 Oct 2004 15:41:20 -0400, Ophir Prusak <prusak at gmail.com> wrote:
> 
>>Just curious, why are you exploding the string into an array?
>>You can just do:
>>
>>   function highlight($keyword, $text) {
>>                $text = preg_replace('/\b' . $keyword .
>>'\b/i','<b>\\0</b>',$text);
>>                return $text;
>>
>>
>>   }
>>
>>On Tue, 19 Oct 2004 14:59:52 -0400, Mark Armendariz <nyphp at enobrev.com> wrote:
>>
>>>>I am able to search the word using the stristr()
>>>>function in php. This function is non-case sensitive.
>>>>However, I want to display the searched word in the line as highlighted in
>>>
>>>a
>>>
>>>>different color than the line.
>>>
>>>I wasn't sure if you wanted to return a line from the text (which Dan seems
>>>to have taken care of pretty well) or if you just wanted to replace words
>>>with formatted versions of themselves.  Here's a really basic function I use
>>>to do the latter with multiple keywords (sep. by spaces):
>>>
>>><?php
>>>   function highlight($keywords, $text) {
>>>       $keywords = trim($keywords);
>>>
>>>       if (strlen($keywords)) {
>>>           $keywords = explode(' ', $keywords);
>>>
>>>           if (count($keywords)) {
>>>               foreach($keywords as $keyword) {
>>>                       // you could, of course use whatever html formatting
>>>you want here
>>>                   $text = preg_replace('/(' . $keyword . ')/i',
>>>'<b>\\1</b>', $text);
>>>               }
>>>           }
>>>       }
>>>
>>>       return $text;
>>>   }
>>>?>
>>>
>>>Good Luck!
>>>
>>>Mark