php - php - 在数组中添加逗号

Question

我有以下数组，我试图用下面的代码添加逗号，但我没有得到值，它只显示“数组”..

数组值

Array (
[0] => Array ( 
   [0] => 144 [category_id] => 144 ) 
   [1] => Array ( [0] => 98 [category_id] => 98 ) 
   [2] => Array ( [0] => 146 [category_id] => 146 ) 
   [3] => Array ( [0] => 142 [category_id] => 142 )
)

尝试使用逗号显示值的代码

$comma_separated = implode(",", $result_array);
echo $comma_separated;

我得到的输出

Array,Array,Array,Array

请检查我做错了什么

Answer 1

$comma_separated = implode(',', array_map(function($i) { return $i[0]; }, $result_array));
echo $comma_separated;