json_decode

You can use the PHP json_decode() function to convert the JSON encoded string into appropriate PHP data type.
By default the json_decode() function returns an object.

<?php // Store JSON data in a PHP variable $json = '{"Peter":65,"Harry":80,"John":78,"Clark":90}'; var_dump(json_decode($json)); ?>

output:
object(stdClass)#1 (4) { ["Peter"]=> int(65) ["Harry"]=> int(80) ["John"]=> int(78) ["Clark"]=> int(90) }

you can optionally specify a second parameter $assoc which accepts a boolean value that when set as true JSON objects are decoded into associative arrays. It is false by default.

<?php // Store JSON data in a PHP variable $json = '{"Peter":65,"Harry":80,"John":78,"Clark":90}'; var_dump(json_decode($json, true)); ?>

array(4) { ["Peter"]=> int(65) ["Harry"]=> int(80) ["John"]=> int(78) ["Clark"]=> int(90) }