Question

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Replace a list of emoticons with their images

i’m developing a website where i want to give users possibility to put smiles on posts.
My (just functional) idea is to use array in this way:

$emoticons = array(
array("17.gif",":)"),
array("6.jpg",":P"),
.....
array("9.jpg",":'("),
array("5.gif","X)")
);

with image on [0] and emoticon on [1].
And on each $post:

foreach($emoticons as $emoticon){
     $quoted_emoticon = preg_quote($emoticon[1],"#");
     $match = '#(?!<\w)(' . $quoted_emoticon .')(?!\w)#';
     $post = preg_replace($match,'<img src="images/emoticons/'.$emoticon[0].'">',$post);
}

This is working good, but my problem is '#(?!<\w)(' and ')(?!\w)#' because I want emoticons to apply only when preceding characters are “begin” (^) or “blank” and succeeding characters are “end” ($) or “blank”. What is the right regex to do this?

Answer 1

I think you want the positive look behind and positive look ahead.

Example:

(?<=\s|^)(\:\))(?=\s|$)

Your example updated:

foreach($emoticons as $emoticon){
     $quoted_emoticon = preg_quote($emoticon[1],"#");
     $match = '(?<=\s|^)(' . $quoted_emoticon .')(?=\s|$)';
     $post = preg_replace($match,'<img src="images/emoticons/'.$emoticon[0].'">',$post);
}