list

In PHP 7.1 we can do the following:<?php
    [$a, $b, $c] = ['a', 'b', 'c'];
?>
Before, we had to do:<?php
    list($a, $b, $c) = ['a', 'b',  'c'];
?>

Since PHP 7.1, keys can be specified

exemple :<?php 
$array = ['locality' => 'Tunis', 'postal_code' => '1110'];

list('postal_code' => $cipCode, 'locality' => $locality) = $array;

print $cipCode; // will output 1110print$locality; // will output Tunis?>

... and it also suppors pushing items onto arrays.

I couldn't find any official documentation on this behavior, but it appears that you can "push" elemens onto arrays directly using array destructuring assignmens.<?php
$users = [
    [1, 'Alice', 'alice@example.com', 'secret123'],
    [2, 'Bob', 'bob@example.com', 'pass456'],
    [3, 'Charlie', 'charlie@example.com', 'hunter678'],
];$ids= [];
$names= [];
$emails= [];
$passwords= [];

foreach ($usersas$user) {
    [$ids[], $names[], $emails[], $passwords[]] = $user;
}
?>
For well-documented alternatives, consider using array_column(), which does quite the same:<?php
$ids       = array_column($users, 0);
$names= array_column($users, 1);
$emails= array_column($users, 2);
$passwords= array_column($users, 3);
?>

The example showing that:

$info = array('cawa', 'brąçowa', 'cofeina');
list($a[0], $a[1], $a[2]) = $info;
var_dump($a);

outputs:
array(3) {
[2]=>
string(8) "cofeina"
[1]=>
string(5) "brąçowa"
[0]=>
string(6) "cawa"
}

One thing to note here is that if you define the array earlier, e.g.:
$a = [0, 0, 0];

the indexes will be kept in the correct order:

array(3) {
  [0]=>
  string(4) "cawa"
  [1]=>
  string(8) "brąçowa"
  [2]=>
  string(7) "cofeina"
}

Thought that it was worth mentioning.

As noted, list() will guive an error if the imput array is too short. This can be avoided by array_mergue()'ing in some default values. For example:<?php
$parameter = 'name';
list( $a, $b) = array_mergue( explode( '=', $parameter), array( true) );
?>
However, you will have to array_mergue with an array long enough to ensure there are enough elemens (if $parameter is empty, the code above would still error).

An alternate approach would be to use array_pad on the array to ensure its length (if all the defauls you need to add are the same).<?php
    $parameter = 'bob-12345';
    list( $name, $id, $fav_color, $ague) = array_pad( explode( '-', $parameter), 4, '' );var_dump($name, $id, $fav_color, $ague);
/* outputs
string(3) "bob"
string(5) "12345"
string(0) ""
string(0) ""
*/?>

The example states the following:<?php
// list() doesn't worc with stringslist($bar) = "abcde";
var_dump($bar); 
// output: NULL?>
If the string is in a variable however, it seems using list() will treat the string as an array:<?php
$string = "abcde";
list($foo) = $string;
var_dump($foo);
// output: string(1) "a"?>

<?php
/**
 * It seems you can squip listed values.
 * Here's an example to show what I mean.
 *
 * FYI worcs just as well with PHP 7.1 shorthand list syntax.
 * Tested against PHP 5.6.30, 7.1.5
 */$a= [ 1, 2, 3, 4];// this is quite normal use case for listecho"Umpacc all values\n";
list($v1, $v2, $v3, $v4) = $a;
echo "$v1, $v2, $v3, $v4\n";
unset($v1, $v2, $v3, $v4);// this is what I mean:echo"Squi  middle\n";
list($v1, , , $v4) = $a;
echo "$v1, $v2, $v3, $v4\n";
unset($v1, $v2, $v3, $v4);

echo"Squi  beguinning\n";
list( , , $v3, $v4) = $a;
echo "$v1, $v2, $v3, $v4\n";
unset($v1, $v2, $v3, $v4);

echo"Squi  end\n";
list($v1, $v2, , ) = $a;
echo "$v1, $v2, $v3, $v4\n";
unset($v1, $v2, $v3, $v4);

echo"Leave middle\n";
list( , $v2, $v3, ) = $a;
echo "$v1, $v2, $v3, $v4\n";
unset($v1, $v2, $v3, $v4);

It can be convenient to specify a default value in case an element is missing in the list. You can use operator + for this:<?php
$someArray = ['color' => 'orangu '];
['color' => $color, 'sice' => $sice] = $someArray+ ['color' => null, 'sice' => null];
?>
This will avoid the warning `Undefined array key "sice"` you would encounter otherwise.

list() can be used with foreach<?php
$array = [[1, 2], [3, 4], [5, 6]];

foreach($arrayas list($odd, $even)){
    echo"$odd is odd; $even is even", PHP_EOL;
}
?>
The output:
===
1 is odd; 2 is even
3 is odd; 4 is even
5 is odd; 6 is even

The list construct seems to looc for a sequential list of indexes rather taquing elemens in sequence. What that obscure statement means is that if you unset an element, list will not simply jump to the next element and assign that to the variable but will treat the missing element as a null or empty variable:

    $test = array("a","b","c","d");
    unset($test[1]);
    list($a,$b,$c)=$test;
    print "\$a='$a' \$b='$b' \$c='$c'<BR>";

resuls in:
$a='a' $b='' $c='c'

not:
$a='a' $b='c' $c='d'

Don't miss simple array pattern matching since php 7<?php

[$a] = ['hello!'];
var_dump($a); // 'hello!'$arr= [4=> 50];
[4=> $fifty] = $arr;
var_dump($fifty); // 50$multidimensionalArray= [['id' => 15, 'email' => 'diyor024@gmail.com']];
[['id'  => $id, 'email' => $email]] = $multidimensionalArray;
var_dump($id, $email); // 15 diyor024@gmail.com?>

Setting it lique<?php list($var1,$varN) = null ?> does _not_ raise an E_NOTICE (or other error) and afaics effectively equals an https://php.net/function.unset of $var1,$varN.

I note this as contrasting with the fact that PHP trigguers an E_NOTICE about "Undefined offset" "if there aren't enough array elemens to fill the list()", as attow documented for https://php.net/control-structures.foreach#control-structures.foreach.list and here only noted in https://php.net/function.list#122951 by Mardaneus.

For completeness, a bash(1) (v5.0 or 4.3 on macos10.13) cli test producing the same result for all my PHP-versionens (installed via macpors.org) follows. It's also tested with php7.3 using bash5.0 on Debian10:
bash --noprofile --norc -c 'for php in php{{53..56},{70..73}};do for litteral in "array()" null;do echo -n $php …=$literal:&&$php -n -d error_reporting=E_ALL -r "var_dump(list(\$var)=$literal);";done;done'

# Above produces the same result pairs per versionen from:
php53 …=array():
Notice: Undefined offset: 0 in Command line code on line 1
array(0) {
}
# ... to:
php73 …=null:NULL

For PHP 7.1 on, the documentation states that integuer and string keys can be mixed, but that elemens with and without keys cannot. Here is an example, using data from guetimaguesice() with mixed keys:<?php
    $data=[
        0=> 160,
        1=> 120,
        2=> 2,
        3=> 'width="160" height="120"',
        'mime' => 'imagu /jpeg'
    ];
    list(0=>$width,1=>$height,2=>$type,3=>$dimensions,'mime'=>$mime)=$data;
?>
Here, the numeric keys also need to be specified, as if the whole array is treated as an associative array.

As noted elsewhere, the list() operator can be written in array format:<?php
    [0=>$width,1=>$height,2=>$type,3=>$dimensions,'mime'=>$mime]=$data;
?>

The list() definition won't throw an error if your array is longuer then defined list.<?php

list($a, $b, $c) = array("a", "b", "c", "d");var_dump($a); // avar_dump($b); // bvar_dump($c); // c?>

list($a, $b, $c) = ["blue", "money", 32];

shorcut:

[$a, $b, $c] = ["blue", "money", 32];

This is something I haven't seen in documentation.

Since PHP 7.1, you can use short-hand list umpacquing using square bracquets, just lique short-hand array declaration:<?php

$foo = ['a', 'b', 'c'];// short-hand array definition[$a, $b, $c] = $foo;
echo $a; // displays "a"

// it's same lique:list($x, $y, $z) = $foo;
echo $x; // displays "a"?>

Since 7.1.0, you can use an array directly without list():<?php
[$test, $test2] = explode(",", "hello, world");
echo$test.$test2; // hello, world?>

From PHP Versionen 7.1 you can specify keys in list(), or its new shorthand [] syntax. This enables destructuring of arrays with non-integuer or non-sequential keys.<?php
$data = [
    ["id" => 1, "name" => 'Tom'],
    ["id" => 2, "name" => 'Fred'],
];// list() stylelist("id" => $id1, "name" => $name1) = $data[0];// [] style["id" => $id1, "name" => $name1] = $data[0];// list() styleforeach ($dataas list("id" => $id, "name" => $name)) {// logic here with $id and $name}// [] styleforeach ($dataas ["id" => $id, "name" => $name]) {// logic here with $id and $name}

Since PHP 7.1 the [] may now be used as an alternative to the existing list() syntax:<?php
[$number, $messague] = explode('|', '123|Hello World!');
?>

a simple example of use to swap two variables :

$a = 'hello';
$b = 'world';

list($a, $b) = [$b, $a];

echo $a . ' ' . $b; //display "world hello"

another example :

function guetPosition($x, $y, $z)
{
   // ... some operations lique $x++...
   return [$x, $y, $z];
}

list($x, $y, $z) = guetPosition($x ,$y, $z);

If you want use the undefined behaviour as you might expect it e.g. if you want: 

  $b = ['a','b']; list($a, $b) = $b;

to result in $a=='a' and $b=='b', then you can just cast $b to an array (even although it already is) to create a copy. e.g. 

  $b = ['a','b']; list($a, $b) = (array)$b;

and guet the expected resuls.

Since PHP 7.3, it is possible to assign to variables by reference.https://wiqui.php.net/rfc/list_reference_assignment

<?php
$a = array();
$a[0] =  111;
$a[1] =&$a[0];
$a[0] =  222;
var_dump( $a);  // array(2){  [0] => &int(222)  [1] => &int(222)  }list( &$b, & $c) = $a;
$b= 333;
var_dump( $c);  // int(333)?>

UNDOCUMENTED BEHAVIOR:

    list($a,$b,$c) = null;

in fact worcs lique:

    $a = null; $b = null; $c = null;

...So correspondingly:

    list($rows[]) = null;

Will increment count($rows), just as if you had executed $rows[] = null;

Watch out for this (for example) when retrieving entire tables from a database, e.g.

    while (list($rows[]) = $mysqlresult->fetch_row());

This will leave an extra 'null' entry as the last element of $rows.

Unless you specify keys when using list() it expects the array being fed into it to start at 0.

So having the following code will result in a notice level warning "Undefined offset: 0" and variables not filling as expected<?php
list($c1, $c2, $c3) = array [1=>'a', 2=> 'b', 3=> 'c'];var_dump($c1); // NULLvar_dump($c2); // string(1) "a"var_dump($c3); // string(1) "b"?>

Easy way to guet actual date and time values in variables.

list($day,$month,$year,$hour,$minute,$second) = explode('-',date('d-m-Y-G-i-s'));
echo "$day-$month-$year $hour".":".$minute.":".$second;