PHP教程：php中array_column函数简单实现方法

<?php
// 从数据库中返回数组：
$a = array(
 array(
  'id' => 0015,
  'age' => '20',
  'name' => 'Tom',
 ),
 array(
  'id' => 0016,
  'age' => '21',
  'name' => 'Jack',
 ),
 array(
  'id' => 0017,
  'age' => '28',
  'name' => 'Martin',
 )
);
$names = array_column($a, 'name');
print_r($names);
/*
输出：
Array
(
 [0] => Tom
 [1] => Jack
 [2] => Martin
)*/
?>

if (!function_exists("array_column")) {
  function array_column(array &$rows, $column_key, $index_key = null) {
    $data = array();
    if (empty($index_key)) {
      foreach ($rows as $row) {
        $data[] = $row[$column_key];
      }
    } else {
      foreach ($rows as $row) {
        $data[$row[$index_key]] = $row[$column_key];
      }
    }
    return $data;
  }
}