- array_map: documentation ( source)
- implode: documentation ( source)
- array_keys: documentation ( source)
<?php
$array = array(
3 => 15,
30 => 1,
1 => 1
);
$string = implode( array_map(
function($v, $k) {
return "$k:$v;";
}, $array, array_keys($array) )
);
echo $string;