How to convert JSON Objects to PHP Associative Arrays using the json_decode() function?

Actually, JSON Objects match better with PHP Associative Arrays than PHP Objects. You can force json_decode() function to turn return PHP Associative Arrays for any JSON Objects by giving the second argument as "true". Default of the second argument is "false".

There are different ways to access properties in the output PHP associative array:

• $array["property_name"] - Returns the property value of the given property name. The property name is also called the key of a give element in the associative array.
• count($array) - Returns the number of properties in the associative array.

Here is a PHP example that shows you how to access properties from the associative array returned by json_decode():

<?php
# json_decode_associative_array.php
# Copyright (c) FYIcenter.com 

   $json = '{"site":"dev.fyicenter.com","topics":{"PHP":"Y","JSON":"Y"}}';
   print("\nInput: ".$json."\n");

# Decoded into an array
   $array = json_decode($json,true);
   print("\nOutput Array:\n");
   print("   Type: ".gettype($array)."\n");
   print("   Size: ".count($array)."\n");
   print("   ['site']: ".$array["site"]."\n");
   print("   ['topics']['JSON']: ".$array["topics"]["JSON"]."\n");

# Dump the array
   print("\nOutput Array Dump:\n");
   var_dump($array);

# Decoded into an object
   $obj = json_decode($json,false);
   print("\nOutput Object:\n");
   print("   Type: ".gettype($obj)."\n");
   print("   ->site: ".$obj->site."\n");
   print("   ->topics->JSON: ".$obj->topics->JSON."\n");

# Dump the object
   print("\nOutput Object Dump:\n");
   var_dump($obj);
?>

If you run the above PHP code through the PHP engine, you get the following output:

>\fyicenter\php\php.exe json_decode_sociative_array.php

Input: {"site":"dev.fyicenter.com","topics":{"PHP":"Y","JSON":"Y"}}

Output Array:
   Type: array
   Size: 2
   ['site']: dev.fyicenter.com
   ['topics']['JSON']: Y

Output Array Dump:
array(2) {
  ["site"]=>
  string(17) "dev.fyicenter.com"
  ["topics"]=>
  array(2) {
    ["PHP"]=>
    string(1) "Y"
    ["JSON"]=>
    string(1) "Y"
  }
}

Output Object:
   Type: object
   ->site: dev.fyicenter.com
   ->topics->JSON: Y

Output Object Dump:
object(stdClass)#1 (2) {
  ["site"]=>
  string(17) "dev.fyicenter.com"
  ["topics"]=>
  object(stdClass)#2 (2) {
    ["PHP"]=>
    string(1) "Y"
    ["JSON"]=>
    string(1) "Y"
  }
}

⇒ json_last_error_msg() - PHP JSON Error Message

⇐ json_decode() - JSON Object to PHP Object

⇑ Using JSON in PHP

⇑⇑ JSON Tutorials