Decoding JSON in PHP can't access keys

If you add a second parameter boolan true to json_decode like

$obj = json_decode($result[0], true);

Then you will get associative array instead of an object.

and can access values through keys like

echo $obj['username'];

$result = '[ { "_id" : { "$oid" : "5237d438e4b07666dcca4896"} , 
    "username" : "user" , "password" : "asdf"} ]';
$obj = json_decode($result);
var_dump($obj);
/**
 * Array containg object. So now $obj is just an array
 * 
array (size=1)
  0 => 
    object(stdClass)[1]
      public '_id' => 
        object(stdClass)[2]
          public '$oid' => string '5237d438e4b07666dcca4896' (length=24)
      public 'username' => string 'user' (length=4)
      public 'password' => string 'asdf' (length=4)
 * 
 * 
 * Key 0 contains object properties _id; username; password
 * 

 */

echo $obj[0]->username;  // user

Try to use this:

$json = json_decode($result);
echo $json[0]->username;

Full example:

<?php
header('Content-Type: text/plain; charset=utf-8');

$result = '[ { "_id" : { "$oid" : "5237d438e4b07666dcca4896"} , 
    "username" : "user" , "password" : "asdf"} ]';

$json = json_decode($result);
echo $json[0]->username;
?>

Result:

user

yes you are right json_decode function returns an array. You need to fetch value from that array. In above case you need to fetch username like below:

echo $json_encode[0]->username;;

depends upon your json.

You can refer this link: