The array_slice Function
The array_slice function slices and returns
a part of an array. The original array remains unchanged.
The first parameter specifies the array to
be sliced. The second parameter specifies
from which element to start slicing, and the third
- how many elements to slice. The second parameter
can be negative - in this case
the count will start from the end (-1 - the last element,
-2 - the second to last, and so on). The third parameter
can be omitted entirely - in this case
the array will be sliced to the very end.
The last optional parameter controls
whether to preserve keys when slicing, true -
preserve, false (default) - do not preserve.
String keys are always preserved, regardless of
the value of this parameter.
Syntax
array_slice(array $array, int $offset, ?int $length = null, bool $preserve_keys = false): array
Example
Let's extract elements starting from the first (has
index 0), 3 pieces:
<?php
$arr = ['a', 'b', 'c', 'd', 'e'];
$res = array_slice($arr, 0, 3);
var_dump($res);
?>
Code execution result:
['a', 'b', 'c']
Example
Let's extract elements starting from the second (has
index 1), 3 pieces:
<?php
$arr = ['a', 'b', 'c', 'd', 'e'];
$res = array_slice($arr, 1, 3);
var_dump($res);
?>
Code execution result:
['b', 'c', 'd']
Example
Let's extract elements starting from the second (has
index 1) to the end of the array. For this, the third
parameter is omitted:
<?php
$arr = ['a', 'b', 'c', 'd', 'e'];
$res = array_slice($arr, 1);
var_dump($res);
?>
Code execution result:
['b', 'c', 'd', 'e']
Example
Let's extract elements starting from the second to last,
2 pieces. For this, the second parameter
is set to -2 (the position of the second to last
element):
<?php
$arr = ['a', 'b', 'c', 'd', 'e'];
$res = array_slice($arr, -2, 2);
var_dump($res);
?>
Code execution result:
['d', 'e']
Example
By default, the array does not preserve keys when slicing:
<?php
$arr = [1 => 'a', 2 => 'b', 3 => 'c', 4 => 'd', 5 => 'c'];
$res = array_slice($arr, 0, 3);
var_dump($res);
?>
Code execution result:
['a', 'b', 'c']
Example
Let's make it so that the keys are preserved. For this, set the last parameter to true:
<?php
$arr = [1 => 'a', 2 => 'b', 3 => 'c'];
$res = array_slice($arr, 0, 3, true);
var_dump($res);
?>
Code execution result:
[1 => 'a', 2 => 'b', 3 => 'c']
Example
String keys are preserved when slicing:
<?php
$arr = ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5];
$res = array_slice($arr, 0, 3);
var_dump($res);
?>
Code execution result:
['a' => 1, 'b' => 2, 'c' => 3]
See Also
-
the
array_splicefunction,
which slices a part of an array, changing the original array in the process
