Replace With Alphabet Position (alt solution)

alphabet_position.php

<?php 

function alphabet_position( $str ) {
	$str = strtolower( $str );

	$alphabetChars = 'abcdefghijklmnoqrstuvwxyz';
	$report=[];
	foreach (str_split($str) as $char) {
		$g = (strpos($alphabetChars, $char) !== false) ? strpos($alphabetChars, $char) : '';
		if ($g!=='') {
			$report[] = $g+1;
		}
	}

	return implode(' ', $report);
}