help with replace

[ngreenwood6]

ok so I have an string with data that I need to be replaced with contents from an array. I need the occurance position replace with the index of  the array. example

 

//here is the setup
$string = "testing %s one %d %s";
array('this',1,'three');

//here is the result
testing this one 2 three

 

the problem I am having is because the %s can occur more than once I cant use str_replace. I am working on a solution with substr_replace but was wondering if anyone had any suggestions on how to do this. When I replace it I also need to run the value through a function so keep that in mind. Also the replace's are stored in an array so they need to be looped through as well.

 

$replaces = array('%s'=>'func_one','%d'=>'func_two');

 

Any help is appreciated.