Regex

Pattern: /d[a-z]f/
String: defabcdef
Result: 2

Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [0] => def
                    [1] => 0
                )

            [1] => Array
                (
                    [0] => def
                    [1] => 6
                )

        )

)