php - 在数组中添加逗号

Question

i have following array, and i have tried to add comma with the following code but i am not getting values its shows "array" only..

Array Value

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 )
)

Tried code to display values with commas

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

output i am getting

Array,Array,Array,Array

please check what i am getting wrong

Answer 1

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