PHP regex for street numbers

usage.php

<?php
/**
 * Get street number from street
 *
 * @param string $street
 *
 * @return string
 */
function get_street_number( $street ) {
	$regex = '/\d.?[^\s]*?[a-zA-Z]?.[?ABC]/i';
	preg_match( $regex, $street, $matches );
	if ( $matches ) return str_replace( ' ', '', $matches );
	$regex = '/\d.?[^\s]*?[a-zA-Z]?/i';
	preg_match( $regex, $street, $matches );
	return str_replace( ' ', '', $matches );
}

echo get_street_number( 'Teststrasse 11B' ); // 11B
echo get_street_number( 'Teststrasse 2' ); // 2
echo get_street_number( 'Teststrasse 11B - Wohnung 200' ); // 11B
echo get_street_number( 'Teststrasse 11 B - Wohnung 200' ); // 11B
echo get_street_number( 'Teststrasse 5 A' ); // 5A