list

Assign variables as if they were an array

array **list** mixed $var mixed $vars

Like , this is not really a function, but a language construct. is used to assign a list of variables in one operation. Only arrays and objects that implement can be unpacked. expressions can not be completely empty. array``listArrayAccesslist

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

As of PHP 7.1.0, 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 . listarray destructuring section

Opmerking: > Attempting to access an array key which has not been defined is the same as accessing any other undefined variable: an -level error message (-level prior to PHP 8.0.0) will be issued, and the result will be null. E_WARNING``E_NOTICE

Attempting to unpack a scalar assigns null to all variables. Attempting to unpack an object that does not implement ArrayAccess is a fatal error.

varA variable.

varsFurther variables.

Returns the assigned array.

Voorbeeld: 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
?>

**Voorbeeld: An example use of **

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

**Voorbeeld: Using nested **

<?php

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

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

?>

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

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

Voorbeeld: and order of index definitions

<?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  syntax):
`list`

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"

Voorbeeld: with keys

 As of PHP 7.1.0  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.
`list`

<?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";

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

2, 4

each``array``extract

Vorige ← ksort Volgende natcasesort →

list

list

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