php获取二维数组中的某个值

<?php
$arr  =array(
array('field_name'=>'值1','field_id'=>'d9','create_time'=>1489734050),
array('field_name'=>'值2','field_id'=>'d10','create_time'=>1489734050),
array('field_name'=>'值3','field_id'=>'d11','create_time'=>1489734050),
array('field_name'=>'值4','field_id'=>'d12','create_time'=>1489734050)
);

$result = array();

foreach ($arr  $key => $value) {
        $result[] = $value['create_time'];

}