How to loop through this json decoded data in PHP?

You can use json_decode() It will convert your json into array.

e.g,

$json_array = json_decode($your_json_data); // convert to object array
$json_array = json_decode($your_json_data, true); // convert to array

Then you can loop array variable like,

foreach($json_array as $json){
   echo $json['key']; // you can access your key value like this if result is array
   echo $json->key; // you can access your key value like this if result is object
}

Try like following codes:

$json_string = '[{"productId":"epIJp9","name":"Product A","amount":"5","identifier":"242"},{"productId":"a93fHL","name":"Product B","amount":"2","identifier":"985"}]';

$array = json_decode($json_string);

foreach ($array as $value)
{
   echo $value->productId; // epIJp9
   echo $value->name; // Product A
}

Get Count

echo count($array); // 2

Did you check the manual ?

http://www.php.net/manual/en/function.json-decode.php

Or just find some duplicates ?

How to convert JSON string to array

Use GOOGLE.

json_decode($json, true);

Second parameter. If it is true, it will return array.

You can try the code at php fiddle online, works for me

 $list = '[{"productId":"epIJp9","name":"Product A","amount":"5","identifier":"242"},{"productId":"a93fHL","name":"Product B","amount":"2","identifier":"985"}]';

$decoded_list = json_decode($list); 

echo count($decoded_list);
print_r($decoded_list);