- array_combine: documentation ( source)
- print_r: documentation ( source)
- preg_match_all: documentation ( source)
<?php
$string = 'id:5918351498722606 sub:001 dlvrd:001 submit date:1410311037 done date:1410311038
stat:DELIVRD err:000 text:New HTTP Test TxtN';
preg_match_all('/(?:^|\s+)([^:]+):([^:]+$|[^\s]+)/', $string, $matches);
$output = array_combine($matches[1], $matches[2]);
print_r($output);