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(PHP 4, PHP 5, PHP 7, PHP 8)
array_pad — Pad array to the specified length with a value
array_pad(array $array, int $length, mixed $value): array
array_pad()
returns a copy of the
array
padded to size specified by
length
with value
value
. If
length
is positive then the array is padded on the right, if it's negative then on the left. If the absolute value of
length
is less than or equal to the length of the
array
then no padding takes place. It is possible to add at most 1048576 elements at a time.
array
Initial array of values to pad.
length
New size of the array.
value
Value to pad if
array
is less than
length
.
Returns a copy of the
array
padded to size specified by
length
with value
value
. If
length
is positive then the array is padded on the right, if it's negative then on the left. If the absolute value of
length
is less than or equal to the length of the
array
then no padding takes place.
Example #1 array_pad() example
<?php
$input = array(12, 10, 9);
$result = array_pad($input, 5, 0);
// result is array(12, 10, 9, 0, 0)
$result = array_pad($input, -7, -1);
// result is array(-1, -1, -1, -1, 12, 10, 9)
$result = array_pad($input, 2, "noop");
// not padded
?>
(PHP 4, PHP 5, PHP 7, PHP 8)
array_pop — Pop the element off the end of array
array_pop(array &$array): mixed
array_pop()
pops and returns the value of the last element of
array
, shortening the
array
by one element.
Note : This function will reset() the array pointer of the input array after use.
array
The array to get the value from.
Returns the value of the last element of
array
. If
array
is empty,
null
will be returned.
Example #1 array_pop() example
<?php
$stack = array("orange", "banana", "apple", "raspberry");
$fruit = array_pop($stack);
print_r($stack);
?>
After this, $stack will have only 3 elements:
Array
(
[0] => orange
[1] => banana
[2] => apple
)
and
raspberry
will be assigned to
$fruit
.
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
array_product — Calculate the product of values in an array
array_product(array $array): int|float
array_product() returns the product of values in an array.
array
The array.
Returns the product as an integer or float.
Example #1 array_product() examples
<?php
$a = array(2, 4, 6, 8);
echo "product(a) = " . array_product($a) . "\n";
echo "product(array()) = " . array_product(array()) . "\n";
?>
The above example will output:
product(a) = 384 product(array()) = 1
(PHP 4, PHP 5, PHP 7, PHP 8)
array_push — Push one or more elements onto the end of array
array_push(array &$array, mixed ...$values): int
array_push()
treats
array
as a stack, and pushes the passed variables onto the end of
array
. The length of
array
increases by the number of variables pushed. Has the same effect as:
<?php
$array[] = $var;
?>
Note : If you use array_push() to add one element to the array, it's better to use
$array[] =because in that way there is no overhead of calling a function.
Note : array_push() will raise a warning if the first argument is not an array. This differed from the
$var[]behaviour where a new array was created, prior to PHP 7.1.0.
array
The input array.
values
The values to push onto the end of the
array
.
Returns the new number of elements in the array.
| Version | Description |
|---|---|
| 7.3.0 | This function can now be called with only one parameter. Formerly, at least two parameters have been required. |
Example #1 array_push() example
<?php
$stack = array("orange", "banana");
array_push($stack, "apple", "raspberry");
print_r($stack);
?>
The above example will output:
Array
(
[0] => orange
[1] => banana
[2] => apple
[3] => raspberry
)
(PHP 4, PHP 5, PHP 7, PHP 8)
array_rand — Pick one or more random keys out of an array
array_rand(array $array, int $num = 1): int|string|array
Picks one or more random entries out of an array, and returns the key (or keys) of the random entries.
This function does not generate cryptographically secure values, and must not be used for cryptographic purposes, or purposes that require returned values to be unguessable.
If cryptographically secure randomness is required, the Random\Randomizer may be used with the Random\Engine\Secure engine. For simple use cases, the random_int() and random_bytes() functions provide a convenient and secure API that is backed by the operating system’s CSPRNG .
array
The input array.
num
Specifies how many entries should be picked.
When picking only one entry,
array_rand()
returns the key for a random entry. Otherwise, an array of keys for the random entries is returned. This is done so that random keys can be picked from the array as well as random values. If multiple keys are returned, they will be returned in the order they were present in the original array. Trying to pick more elements than there are in the array will result in an
E_WARNING
level error, and NULL will be returned.
| Version | Description |
|---|---|
| 7.1.0 | The internal randomization algorithm has been changed to use the » Mersenne Twister Random Number Generator instead of the libc rand function. |
Example #1 array_rand() example
<?php
$input = array("Neo", "Morpheus", "Trinity", "Cypher", "Tank");
$rand_keys = array_rand($input, 2);
echo $input[$rand_keys[0]] . "\n";
echo $input[$rand_keys[1]] . "\n";
?>
(PHP 4 >= 4.0.5, PHP 5, PHP 7, PHP 8)
array_reduce — Iteratively reduce the array to a single value using a callback function
array_reduce(array $array, callable $callback, mixed $initial = null): mixed
array_reduce()
applies iteratively the
callback
function to the elements of the
array
, so as to reduce the array to a single value.
array
The input array.
callback
callback(mixed $carry, mixed $item): mixed
carry
Holds the return value of the previous iteration; in the case of the first iteration it instead holds the value of
initial
.
item
Holds the value of the current iteration.
initial
If the optional
initial
is available, it will be used at the beginning of the process, or as a final result in case the array is empty.
Returns the resulting value.
If the array is empty and
initial
is not passed,
array_reduce()
returns
null
.
| Version | Description |
|---|---|
| 8.0.0 |
If
callback
expects a parameter to be passed by reference, this function will now emit an
E_WARNING
.
|
Example #1 array_reduce() example
<?php
function sum($carry, $item)
{
$carry += $item;
return $carry;
}
function product($carry, $item)
{
$carry *= $item;
return $carry;
}
$a = array(1, 2, 3, 4, 5);
$x = array();
var_dump(array_reduce($a, "sum")); // int(15)
var_dump(array_reduce($a, "product", 10)); // int(1200), because: 10*1*2*3*4*5
var_dump(array_reduce($x, "sum", "No data to reduce")); // string(17) "No data to reduce"
?>