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(PHP 4, PHP 5, PHP 7, PHP 8)
array_reverse — Return an array with elements in reverse order
array_reverse(array $array, bool $preserve_keys = false): array
Takes an input
array
and returns a new array with the order of the elements reversed.
array
The input array.
preserve_keys
If set to
true
numeric keys are preserved. Non-numeric keys are not affected by this setting and will always be preserved.
Returns the reversed array.
Example #1 array_reverse() example
<?php
$input = array("php", 4.0, array("green", "red"));
$reversed = array_reverse($input);
$preserved = array_reverse($input, true);
print_r($input);
print_r($reversed);
print_r($preserved);
?>
The above example will output:
Array
(
[0] => php
[1] => 4
[2] => Array
(
[0] => green
[1] => red
)
)
Array
(
[0] => Array
(
[0] => green
[1] => red
)
[1] => 4
[2] => php
)
Array
(
[2] => Array
(
[0] => green
[1] => red
)
[1] => 4
[0] => php
)
(PHP 4 >= 4.0.5, PHP 5, PHP 7, PHP 8)
array_search — Searches the array for a given value and returns the first corresponding key if successful
array_search(mixed $needle, array $haystack, bool $strict = false): int|string|false
Searches for
needle
in
haystack
.
needle
The searched value.
Note :
If
needleis a string, the comparison is done in a case-sensitive manner.
haystack
The array.
strict
If the third parameter
strict
is set to
true
then the
array_search()
function will search for
identical
elements in the
haystack
. This means it will also perform a strict type comparison of the
needle
in the
haystack
, and objects must be the same instance.
Returns the key for
needle
if it is found in the array,
false
otherwise.
If
needle
is found in
haystack
more than once, the first matching key is returned. To return the keys for all matching values, use
array_keys()
with the optional
search_value
parameter instead.
This function may return Boolean
false
, but may also return a non-Boolean value which evaluates to
false
. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.
Example #1 array_search() example
<?php
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');
$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array); // $key = 1;
?>
(PHP 4, PHP 5, PHP 7, PHP 8)
array_shift — Shift an element off the beginning of array
array_shift(array &$array): mixed
array_shift()
shifts the first value of the
array
off and returns it, shortening the
array
by one element and moving everything down. All numerical array keys will be modified to start counting from zero while literal keys won't be affected.
Note : This function will reset() the array pointer of the input array after use.
array
The input array.
Returns the shifted value, or
null
if
array
is empty or is not an array.
Example #1 array_shift() example
<?php
$stack = array("orange", "banana", "apple", "raspberry");
$fruit = array_shift($stack);
print_r($stack);
?>
The above example will output:
Array
(
[0] => banana
[1] => apple
[2] => raspberry
)
and
orange
will be assigned to
$fruit
.
(PHP 4, PHP 5, PHP 7, PHP 8)
array_slice — Extract a slice of the array
array_slice( array $array, int $offset, ?int $length = null, bool $preserve_keys = false ): array
array_slice()
returns the sequence of elements from the array
array
as specified by the
offset
and
length
parameters.
array
The input array.
offset
If
offset
is non-negative, the sequence will start at that offset in the
array
.
If
offset
is negative, the sequence will start that far from the end of the
array
.
Note :
The
offsetparameter denotes the position in the array, not the key.
length
If
length
is given and is positive, then the sequence will have up to that many elements in it.
If the array is shorter than the
length
, then only the available array elements will be present.
If
length
is given and is negative then the sequence will stop that many elements from the end of the array.
If it is omitted, then the sequence will have everything from
offset
up until the end of the
array
.
preserve_keys
Note :
array_slice() will reorder and reset the integer array indices by default. This behaviour can be changed by setting
preserve_keystotrue. String keys are always preserved, regardless of this parameter.
Returns the slice. If the offset is larger than the size of the array, an empty array is returned.
Example #1 array_slice() examples
<?php
$input = array("a", "b", "c", "d", "e");
$output = array_slice($input, 2); // returns "c", "d", and "e"
$output = array_slice($input, -2, 1); // returns "d"
$output = array_slice($input, 0, 3); // returns "a", "b", and "c"
// note the differences in the array keys
print_r(array_slice($input, 2, -1));
print_r(array_slice($input, 2, -1, true));
?>
The above example will output:
Array
(
[0] => c
[1] => d
)
Array
(
[2] => c
[3] => d
)
Example #2 array_slice() and one-based array
<?php
$input = array(1 => "a", "b", "c", "d", "e");
print_r(array_slice($input, 1, 2));
?>
The above example will output:
Array
(
[0] => b
[1] => c
)
Example #3 array_slice() and array with mixed keys
<?php
$ar = array('a'=>'apple', 'b'=>'banana', '42'=>'pear', 'd'=>'orange');
print_r(array_slice($ar, 0, 3));
print_r(array_slice($ar, 0, 3, true));
?>
The above example will output:
Array
(
[a] => apple
[b] => banana
[0] => pear
)
Array
(
[a] => apple
[b] => banana
[42] => pear
)
(PHP 4, PHP 5, PHP 7, PHP 8)
array_splice — Remove a portion of the array and replace it with something else
array_splice( array &$array, int $offset, ?int $length = null, mixed $replacement = [] ): array
Removes the elements designated by
offset
and
length
from the
array
array, and replaces them with the elements of the
replacement
array, if supplied.
Note :
Numerical keys in
arrayare not preserved.
Note : If
replacementis not an array, it will be typecast to one (i.e.(array) $replacement). This may result in unexpected behavior when using an object ornullreplacement.
array
The input array.
offset
If
offset
is positive then the start of the removed portion is at that offset from the beginning of the
array
array.
If
offset
is negative then the start of the removed portion is at that offset from the end of the
array
array.
length
If
length
is omitted, removes everything from
offset
to the end of the array.
If
length
is specified and is positive, then that many elements will be removed.
If
length
is specified and is negative, then the end of the removed portion will be that many elements from the end of the array.
If
length
is specified and is zero, no elements will be removed.
To remove everything from
offset
to the end of the array when
replacement
is also specified, use
count($input)
for
length
.
replacement
If
replacement
array is specified, then the removed elements are replaced with elements from this array.
If
offset
and
length
are such that nothing is removed, then the elements from the
replacement
array are inserted in the place specified by the
offset
.
Note :
Keys in the
replacementarray are not preserved.
If
replacement
is just one element it is not necessary to put
array()
or square brackets around it, unless the element is an array itself, an object or
null
.
Returns an array consisting of the extracted elements.
| Version | Description |
|---|---|
| 8.0.0 |
length
is nullable now.
|
Example #1 array_splice() examples
<?php
$input = array("red", "green", "blue", "yellow");
array_splice($input, 2);
var_dump($input);
$input = array("red", "green", "blue", "yellow");
array_splice($input, 1, -1);
var_dump($input);
$input = array("red", "green", "blue", "yellow");
array_splice($input, 1, count($input), "orange");
var_dump($input);
$input = array("red", "green", "blue", "yellow");
array_splice($input, -1, 1, array("black", "maroon"));
var_dump($input);
?>
The above example will output:
array(2) {
[0]=>
string(3) "red"
[1]=>
string(5) "green"
}
array(2) {
[0]=>
string(3) "red"
[1]=>
string(6) "yellow"
}
array(2) {
[0]=>
string(3) "red"
[1]=>
string(6) "orange"
}
array(5) {
[0]=>
string(3) "red"
[1]=>
string(5) "green"
[2]=>
string(4) "blue"
[3]=>
string(5) "black"
[4]=>
string(6) "maroon"
}
Example #2 Equivalent statements to various array_splice() examples
The following statements are equivalent:
<?php
// append two elements to $input
array_push($input, $x, $y);
array_splice($input, count($input), 0, array($x, $y));
// remove the last element of $input
array_pop($input);
array_splice($input, -1);
// remove the first element of $input
array_shift($input);
array_splice($input, 0, 1);
// insert an element at the start of $input
array_unshift($input, $x, $y);
array_splice($input, 0, 0, array($x, $y));
// replace the value in $input at index $x
$input[$x] = $y; // for arrays where key equals offset
array_splice($input, $x, 1, $y);
?>
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
array_sum — Calculate the sum of values in an array
array_sum(array $array): int|float
array_sum() returns the sum of values in an array.
array
The input array.
Returns the sum of values as an integer or float;
0
if the
array
is empty.
Example #1 array_sum() examples
<?php
$a = array(2, 4, 6, 8);
echo "sum(a) = " . array_sum($a) . "\n";
$b = array("a" => 1.2, "b" => 2.3, "c" => 3.4);
echo "sum(b) = " . array_sum($b) . "\n";
?>
The above example will output:
sum(a) = 20 sum(b) = 6.9