PHP数组的简写语法

Question

Is this valid PHP syntax or just a shorthand for the documentation? Does anybody have the link to a help page describing this notation?

$array = [
  [1, 2],
  [3, 4],
];

If you have a look at the code examples in the Unpacking nested arrays with list() section on the foreach help page you will see this possibly new notation, however I can't seem to find any help for this.

Answer 1

The new syntax [] was added in PHP 5.4.0 . Check out the documentation on arrays

Answer 2

The page you reference is saying that unpacking the array using list() is new in PHP 5.5, not the short array syntax itself, which was added in PHP 5.4.

PHP 5.5 added the ability to iterate over an array of arrays and unpack the nested array into loop variables by providing a list() as the value.

Answer 3

That is no more than an array of arrays. These two snippets are identical:

$array = [
  [1, 2],
  [3, 4],
];

$array = array(
  array (1, 2),
  array (3, 4),
);

This is documented in the PHP manual page for Arrays and has been possible since PHP 5.4.

Answer 4

Why don't you just test the code? I'm using PHP Version 5.4.7 and it is already valid code. Example:

$array = [
    [1, 2],
    [3, 4],
];
echo '<pre>';
print_r($array);
echo '</pre>';