Multiple Patterns for preg_replace

[dogfighter]

I'm trying to replace words in paragraphs with random words from a database (a-la madlib), but I don't want it to grab partial words. For example, I want it to replace "white" and not part of "whiten" or "whitest". I'm thinking the way to do this is to define individual words as the word preceded by a space and followed by either another space or some form of punctuation...so:

 

" white "

" white."

" white!"

 

I know this will miss the first word in a paragraph since there's usually not a space before it, but I can live with that.

 

The problem is I don't want to do preg_replace 15 different times just to get all instances. And I also want the replace to use the following character... so a match on " white!" should be replaced with " black!" and not " black ".

 

Here's the code I have so far, mostly borrowed from a free example I found online:

 

<?php
function spin($text) {

//While there's pairs of square brackets, spin whats inside of them
while (!(strpos($text,'[') === FALSE) && !(strpos($text,']') === FALSE)) {

//Find the first '['
$leftb = strpos($text,'[');

//Find the first ']'
$rightb = strpos($text,']');

//Split the string up, then (psudo)randomise the item chosen
$spintext = split(',',substr($text,$leftb+1,$rightb-$leftb-1));
$spinselect = trim($spintext[mt_rand(0,count($spintext)-1)]);

//Get the whole string to replace including the brackets
$brackettext = substr($text,$leftb,($rightb-$leftb)+1);

//Replace the [blah,blah2] with whatever item is chosen
$text = str_replace($brackettext,$spinselect,$text);

}

//return the block of modified text
return $text;

}

$tospin = "The quick brown fox.";
$patterns[0] = '/ quick /';
$patterns[1] = '/ brown /';
$patterns[2] = '/ fox /';
$replacements[0] = '[ fast , sluggish, speedy ]';
$replacements[1] = '[ pink , white , yellow , blue ]';
$replacements[2] = '[ bear , snake , bird ]';
ksort($patterns);
ksort($replacements);
$prespin = preg_replace($patterns, $replacements, $tospin);

echo spin($prespin);
?>

 

Can anyone help me with this? I'm a bit out of my league with this one..

[thebadbad]

Word boundaries were made just for this. Example:

 

<?php
$str = 'The whitest color is white.';
echo preg_replace('~\bwhite\b~i', 'black', $str);
?>

[dogfighter]

beautiful, thanks!