- preg_replace_callback: documentation ( source)
- range: documentation ( source)
- sprintf: documentation ( source)
<?php
$number = 43;
$substitutes = range('a', 'j');
$formatted = sprintf('%010d', $number);
$string = preg_replace_callback('.', function ($m) use ($substitutes) {
return $substitutes[$m[0]];
}, $formatted);
echo $string;