String searching and replacing

Cannt get my head around this at all, i need to search a string for a word, and then replace it with another based on an array, the problem being is the word is the same throught so i need to loop through itsome how.

$new_words =array("NewWord1", "NewWord2","NewWord3") ///etc
$needle ="{This}";
$haystack = "My string include {This} and {This} and finally ends in this {This}"

I need to replace the needle with the new_words
I can count the times it occurs and now how to subsrt_replace, but cannt seem to set any offsets or loop for each occurence
Any help would save me a late night???

 

This should work for you:

http//: us3.php.net/manual/en/function.preg-replace.php
http//: us3.php.net/manual/en/function.preg-match-all.php

(grr... can't link yet.)

$new_words[0] = 'NewWord0';
$new_words[1] = 'NewWord1';
$new_words[2] = 'NewWord2';
$new_words[3] = 'NewWord3';
$new_words[4] = 'NewWord4';
$new_words[5] = 'NewWord5';

$needle = '(this)'; //Make sure to include delimiters (in this case ( and ), but any non-alpha/numeric character will work

$haystack = 'this is some text that will have this replaced 3 times. this should work!';

$limit = 1; //limits the maximum number of replacements for $needle in $haystack 

preg_match_all($needle, $haystack, $matches);

$total = count($matches[0]); //How many matches


for($i = 0; $i < $total; $i++) //Loop through and replace as necessary
	$haystack = preg_replace($needle, $new_words[$i], $haystack, $limit);

Code (markup):

-the mole