"Array" Appearing Before JSON Ouput - php

Question

I'm new to PHP and I don't understand why there is an extra word ARRAY infront of the JSON string.
Heres the output of JSON String:
Array{"Users":[{"UserID":"1","FirstName":"lalawee","Email":"12345","Password":null},{"UserID":"2","FirstName":"shadowblade721","Email":"12345","Password":null},{"UserID":"3","FirstName":"dingdang","Email":"12345","Password":null},{"UserID":"4","FirstName":"solidsnake0328","Email":"12345","Password":null}],"success":1}
This is the PHP file:
<?php
/*
* Following code will list all the Users
*/
// array for JSON response
$response = array();
// include db connect class
require_once __DIR__ . '/db_connect.php';
// connecting to db
$db = new DB_CONNECT();
// get all Users from Users table
$result = mysql_query("SELECT * FROM Users") or die(mysql_error());
// check for empty result
if (mysql_num_rows($result) > 0) {
// looping through all results
// Users node
$response["Users"] = array();
while ($row = mysql_fetch_array($result)) {
// temp user array
$user[] = array();
$user["UserID"] = $row["UserID"];
$user["FirstName"] = $row["FirstName"];
$user["Email"] = $row["Email"];
$user["Password"] = $row["Password"];
// push single User into final response array
array_push($response["Users"], $user);
}
// success
$response["success"] = 1;
echo $response;
// echoing JSON response
echo json_encode($response);
}
else {
// no Users found
$response["success"] = 0;
$response["message"] = "No Users found";
// echo no users JSON
echo json_encode($response);
}
?>

Answer 1

Remove
echo $response;
which is printing the word Array. If you try to echo the array, it will display the word 'Array' rather than printing the content of an array itself. Use print_r() function to display the content of an array.
print_r($response);

Answer 2

With the exception of classes that use the __to_string magic method, echo and print will only output the string interpretation of a variable's value. Number types (integers and floats), strings, and (I think) booleans have a straightforward string representation. Any other variable (arrays, objects, resources) will either output nothing, their variable type, or throw a fatal error.
For arrays and objects, print_r() will go through each member/property and attempt to convert it to a string (print_r being shorthand for print_recursive). So print_r($response) will give you the full array.
Bear in mind that generally the full array is only useful to output for debugging. Passing a php string version of an array to javascript is likely to be useless.