Assign variables as if they were an array

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- Assign variables as if they were an array

# list

(PHP 4, PHP 5, PHP 7, PHP 8)

list — Assign variables as if they were an array

### Description

list(mixed `$var`, mixed `...$vars` = ?): array

Like array(), this is not really a function, but a language construct. list() is used to assign a list of variables in one operation. Strings can not be unpacked and list() expressions can not be completely empty.

> Note:

> Before PHP 7.1.0, list() only worked on numerical arrays and assumes the numerical indices start at 0.

As of PHP 7.1.0, list() can also contain explicit keys, allowing for the destructuring of arrays with non-integer or non-sequential keys. For more details on array destructuring, see the array destructuring section.

### Parameters

`var`

  A variable.

`vars`

  Further variables.

### Return Values

Returns the assigned array.

### Changelog

Version | Description
--- | ---
7.3.0 | Support for reference assignments in array destructuring was added.
7.1.0 | It is now possible to specify keys in list(). This enables destructuring of arrays with non-integer or non-sequential keys.

### Examples

Example #1 list() examples

    <?php

    $info = array('coffee', 'brown', 'caffeine');

    // Listing all the variables
    list($drink, $color, $power) = $info;
    echo "$drink is $color and $power makes it special.\n";

    // Listing some of them
    list($drink, , $power) = $info;
    echo "$drink has $power.\n";

    // Or let's skip to only the third one
    list( , , $power) = $info;
    echo "I need $power!\n";

    // list() doesn't work with strings
    list($bar) = "abcde";
    var_dump($bar); // NULL
    ?>

Example #2 An example use of list()

    <?php
    $result = $pdo->query("SELECT id, name FROM employees");
    while (list($id, $name) = $result->fetch(PDO::FETCH_NUM)) {
        echo "id: $id, name: $name\n";
    }
    ?>

Example #3 Using nested list()

    <?php

    list($a, list($b, $c)) = array(1, array(2, 3));

    var_dump($a, $b, $c);

    ?>

    int(1)
    int(2)
    int(3)

Example #4 list() and order of index definitions

The order in which the indices of the array to be consumed by list() are defined is irrelevant.

    <?php
    $foo = array(2 => 'a', 'foo' => 'b', 0 => 'c');
    $foo[1] = 'd';
    list($x, $y, $z) = $foo;
    var_dump($foo, $x, $y, $z);

Gives the following output (note the order of the elements compared in which order they were written in the list() syntax):

    array(4) {
      [2]=>
      string(1) "a"
      ["foo"]=>
      string(1) "b"
      [0]=>
      string(1) "c"
      [1]=>
      string(1) "d"
    }
    string(1) "c"
    string(1) "d"
    string(1) "a"

Example #5 list() with keys

As of PHP 7.1.0 list() can now also contain explicit keys, which can be given as arbitrary expressions. Mixing of integer and string keys is allowed; however, elements with and without keys cannot be mixed.

    <?php
    $data = [
        ["id" => 1, "name" => 'Tom'],
        ["id" => 2, "name" => 'Fred'],
    ];
    foreach ($data as ["id" => $id, "name" => $name]) {
        echo "id: $id, name: $name\n";
    }
    echo PHP_EOL;
    list(1 => $second, 3 => $fourth) = [1, 2, 3, 4];
    echo "$second, $fourth\n";

The above example will output:

    id: 1, name: Tom
    id: 2, name: Fred

    2, 4

### See Also

- each() - Return the current key and value pair from an array and advance the array cursor
- array() - Create an array
- extract() - Import variables into the current symbol table from an array