use php NULL like array

Question

<?php
  ini_set('display_errors',1);
  ini_set('error_reporting',-1);
  $data = null;
  var_export( $data['name']);
  echo PHP_EOL;
  var_dump($data['name']);

Why the result is null, but no notice or warning occured?

Answer 1

Because null is an undefined type, $data['name'] therefore creates its own array.

Answer 2

If you check the data type of $data before assigning null, you will get the undefined variable notice.

echo gettype($data);
$data = null;

After you assigned null to $data, you will see NULL for its value and its data type.

$data = null;
echo gettype($data);
var_dump($data);

According to the documentation of NULL, you're getting NULL for $data['name'] means that it has not been set to any value yet.

The special NULL value represents a variable with no value. NULL is the only possible value of type null.

A variable is considered to be null if:

• it has been assigned the constant NULL.

• it has not been set to any value yet.

• it has been unset().

The following two examples show that the previously defined variable is not auto-converting to array, and keep its original data type.

Example 1:

$data = null;          // $data is null
var_dump($data['name']); // null
var_dump($data[0]);    // null

Example 2:

$data = 'far';  // $data is string
$data[0] = 'b'; // $data is still string
echo $data;     // bar

Answer 3

Just reread documentation about type casting in php.

http://php.net/manual/en/language.types.type-juggling.php

PHP is not so strict as c/c++ or java :-)