- array_column: documentation ( source)
- print_r: documentation ( source)
<?php
$records = array(
array(
'id' => 2135,
'first_name' => 'John',
'last_name' => 'Doe'
),
array(
'id' => -1,
'first_name' => 'Sally',
'last_name' => 'Smith'
),
array(
'id' => -2,
'first_name' => 'Jane',
'last_name' => 'Jones'
),
);
$firstNames = array_column($records, null, 'id');
print_r($firstNames);