PHP preg_replace strings to images - php

Question

When a user wants to send a message, he can use emoticons.
What happens, is that a users clicks on an emoticon, so that it inserts the corresponding text, like this:
:D
Now, after the message has been sent, the other person wants to see it.
What I want is to replace the :D with an image...
Here is what I got:
$patterns = array();
$patterns[0] = '/:)/';
$patterns[1] = '/:(/';
$patterns[2] = '/:D/';
$patterns[3] = '/:C/';
$patterns[4] = '/:A/';
$patterns[5] = '/:H/';
$patterns[6] = '/:L/';
$patterns[7] = '/:O/';
$patterns[8] = '/:S/';
$patterns[9] = '/;)/';
$replacements = array();
$replacements[0] = '<img alt=":)" border="0" src="./images/smileys/happy.png" width="25px" />';
$replacements[1] = '<img alt=":(" border="0" src="./images/smileys/sad.png" width="25px" />';
$replacements[2] = '<img alt=":D" border="0" src="./images/smileys/veryhappy.png" width="25px" />';
$replacements[3] = '<img alt=":C" border="0" src="./images/smileys/cry.png" width="25px" />';
$replacements[4] = '<img alt=":A" border="0" src="./images/smileys/angry.png" width="25px" />';
$replacements[5] = '<img alt=":H" border="0" src="./images/smileys/heart.png" width="25px" />';
$replacements[6] = '<img alt=":L" border="0" src="./images/smileys/love.png" width="25px" />';
$replacements[7] = '<img alt=":O" border="0" src="./images/smileys/nothing.png" width="25px" />';
$replacements[8] = '<img alt=":S" border="0" src="./images/smileys/scared.png" width="25px" />';
$replacements[9] = '<img alt=";)" border="0" src="./images/smileys/wink.png" width="25px" />';
preg_replace($patterns, $replacements, $bericht);
But these aren't the right Regexes...so I get a php error.
In the near future I'd like to take a tutorial on how regexes work, but I hope someone can help me out now.
Is there a simple and quick way to do this? Preferably per pattern like I do now, not in 1 big regex.

Answer 1

Since you don't need regex search patterns you can simply use str_replace.
From manual page:
If you don't need fancy replacing rules (like regular expressions), you should always use this function instead of preg_replace().
$bericht = str_replace($patterns, $replacements, $bericht);

Answer 2

Just escape the parenthesis:
$patterns[0] = '/:\)/';
$patterns[1] = '/:\(/';
$patterns[9] = '/;\)/';
and also, change the last line to:
$bericht = preg_replace($patterns, $replacements, $bericht);

Answer 3

You're replacing fixed strings, so there's absolutely no need to use regex patterns here at all; a straightforward str_replace() will do just fine.
Or better yet, use strtr(), because then you can use an associative array for your replacement data...
$replacements = array(
':)' = '<img alt=":)" border="0" src="./images/smileys/happy.png" width="25px" />',
':(' = '<img alt=":(" border="0" src="./images/smileys/sad.png" width="25px" />',
':D' = '<img alt=":D" border="0" src="./images/smileys/veryhappy.png" width="25px" />',
':C' = '<img alt=":C" border="0" src="./images/smileys/cry.png" width="25px" />',
':A' = '<img alt=":A" border="0" src="./images/smileys/angry.png" width="25px" />',
':H' = '<img alt=":H" border="0" src="./images/smileys/heart.png" width="25px" />',
':L' = '<img alt=":L" border="0" src="./images/smileys/love.png" width="25px" />',
':O' = '<img alt=":O" border="0" src="./images/smileys/nothing.png" width="25px" />',
':S' = '<img alt=":S" border="0" src="./images/smileys/scared.png" width="25px" />',
';)' = '<img alt=";)" border="0" src="./images/smileys/wink.png" width="25px" />',
);
$output = strtr($input, $replacements);
Much simpler!
One thing you should watch out for is inadvertently replacing strings that aren't intended to be emoticons. This is quite a common problem for programs that do this kind of thing. (I've been caught out by Skype plenty of times converting things like (c) and 8) into icons when I didn't intend it to)