list
Assign variables as if they were an array
&reftitle.description;
arraylist
mixedvar
mixedvars
Like array, this is not really a function,
but a language construct. list is used to
assign a list of variables in one operation.
Before PHP 7.1.0, list only worked on numerical arrays and assumes
the numerical indices start at 0.
In PHP 5, list assigns the values starting with the
right-most parameter. In PHP 7, list starts with the
left-most parameter.
If you are using plain variables, you don't have to worry about this. But
if you are using arrays with indices you usually expect the order of the
indices in the array the same you wrote in the list
from left to right, which is not the case in PHP 5, as it's assigned in the
reverse order.
Generally speaking, it is advisable to avoid relying on a specific order
of operation, as this may change again in the future.
&reftitle.parameters;
var
A variable.
vars
Further variables.
&reftitle.returnvalues;
Returns the assigned array.
&reftitle.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.
7.0.0
The order that the assignment operations are performed in has
changed.
7.0.0
list expressions can no longer be completely
empty.
7.0.0
Strings can no longer be unpacked.
&reftitle.examples;
<function>list</function> examples
]]>
An example use of <function>list</function>
| Employee name |
Salary |
query("SELECT id, name, salary FROM employees");
while (list($id, $name, $salary) = $result->fetch(PDO::FETCH_NUM)) {
echo " \n" .
" | $name | \n" .
" $salary | \n" .
"
\n";
}
?>
]]>
Using nested <function>list</function>
]]>
Using <function>list</function> with array indices
]]>
Gives the following output (note the order of the elements compared in
which order they were written in the list syntax):
&example.outputs.7;
string(6) "coffee"
[1]=>
string(5) "brown"
[2]=>
string(8) "caffeine"
}
]]>
&example.outputs.5;
string(8) "caffeine"
[1]=>
string(5) "brown"
[0]=>
string(6) "coffee"
}
]]>
<function>list</function> and order of index definitions
The order in which the indices of the array to be consumed by
list are defined is irrelevant.
'a', 'foo' => 'b', 0 => 'c');
$foo[1] = 'd';
list($x, $y, $z) = $foo;
var_dump($foo, $x, $y, $z);
]]>
Gives the following output (note the order of the elements compared in
which order they were written in the list syntax):
string(1) "a"
["foo"]=>
string(1) "b"
[0]=>
string(1) "c"
[1]=>
string(1) "d"
}
string(1) "c"
string(1) "d"
string(1) "a"
]]>
<function>list</function> with keys
As of PHP 7.1.0 list can now also contain
explicit keys, which can be given as arbitrary expressions.
Mixing of integer and string keys is allowed; however, elements
with and without keys cannot be mixed.
1, "name" => 'Tom'],
["id" => 2, "name" => 'Fred'],
];
foreach ($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";
]]>
&example.outputs;
&reftitle.seealso;
each
array
extract