- preg_replace_callback: documentation ( source)
- strtolower: documentation ( source)
<?php
$str = '$1.1m
Foo
£2,2b
Bar
€99.9';
$lookup = [
'b' => 'million platinum coins',
'm' => 'million gold coins',
'' => 'gold coins',
];
echo preg_replace_callback(
'~[$£€](\d+(?:[.,]\d+)?)([bm]?)~iu',
function($m) use ($lookup) {
return "$m[1] " . $lookup[strtolower($m[2])];
},
$str
);