Search string in array functionality. <?php $array_value = array ( array ( 'id' => 2, 'name' => 'Sammy'), array ( 'id' => 3, 'name' => 'ram'), array ( 'id' => 4, 'name' => 'sam'), array ( 'id' => 2, 'name' => 'sammer') ); $index_array = array_keys( array_filter( $array,function ( $x ) { return preg_match('/^D.*$/',$x['name']); } )); var_dump($index_array); ?>