Online PHP editor | refs for 51N63

<?php $records = array( array( 'id' => 2135 , 'first_name' => 'John' , 'last_name' => 'Doe' , ), array( 'id' => 3245 , 'first_name' => 'Sally' , 'last_name' => 'Smith' , ), array( 'id' => 5342 , 'first_name' => 'Jane' , 'last_name' => 'Jones' , ), array( 'id' => 5623 , 'first_name' => 'Peter' , 'last_name' => 'Doe' , ) ); $first_names = array_column ( $records , 'id' ); print_r ( $first_names );