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.
Parameters
array
Initial array of values to pad.
length
New size of the array.
value
Value to pad if
array
is less than
length
.
Return Values
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.
Examples
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($input,2,"noop");// not padded?>
See Also
array_fill() - Fill an array with values
range() - Create an array containing a range of elements
PHP / array_pop — DevDocs
array_pop
(PHP 4, PHP 5, PHP 7, PHP 8)
array_pop
—
Pop the element off the end of array
Description
array_pop(array&$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.
Parameters
array
The array to get the value from.
Return Values
Returns the value of the last element of
array
. If
array
is empty,
null
will be returned.
array_push
—
Push one or more elements onto the end of array
Description
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;?>
repeated for each passed value.
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
$var[]
behaviour where a new array was created, prior to PHP 7.1.0.
Parameters
array
The input array.
values
The values to push onto the end of the
array
.
Return Values
Returns the new number of elements in the array.
Changelog
Version
Description
7.3.0
This function can now be called with only one parameter. Formerly, at least two parameters have been required.
Picks one or more random entries out of an array, and returns the key (or keys) of the random entries.
Caution
This function does not generate cryptographically secure values, and
must not
be used for cryptographic purposes, or purposes that require returned values to be unguessable.
If cryptographically secure randomness is required, the
Random\Randomizer
may be used with the
Random\Engine\Secure
engine. For simple use cases, the
random_int()
and
random_bytes()
functions provide a convenient and secure
API
that is backed by the operating system’s
CSPRNG
.
Parameters
array
The input array.
num
Specifies how many entries should be picked.
Return Values
When picking only one entry,
array_rand()
returns the key for a random entry. Otherwise, an array of keys for the random entries is returned. This is done so that random keys can be picked from the array as well as random values. If multiple keys are returned, they will be returned in the order they were present in the original array. Trying to pick more elements than there are in the array will result in an
E_WARNING
level error, and NULL will be returned.
Changelog
Version
Description
7.1.0
The internal randomization algorithm has been changed to use the » Mersenne Twister Random Number Generator instead of the libc rand function.
array_reduce()
applies iteratively the
callback
function to the elements of the
array
, so as to reduce the array to a single value.
Parameters
array
The input array.
callback
callback(mixed$carry,mixed$item):mixed
carry
Holds the return value of the previous iteration; in the case of the first iteration it instead holds the value of
initial
.
item
Holds the value of the current iteration.
initial
If the optional
initial
is available, it will be used at the beginning of the process, or as a final result in case the array is empty.
Return Values
Returns the resulting value.
If the array is empty and
initial
is not passed,
array_reduce()
returns
null
.
Changelog
Version
Description
8.0.0
If
callback
expects a parameter to be passed by reference, this function will now emit an
E_WARNING
.
Examples
Example #1
array_reduce()
example
<?phpfunctionsum($carry,$item){$carry+=$item;return$carry;}functionproduct($carry,$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($a,"product",10));// int(1200), because: 10*1*2*3*4*5var_dump(array_reduce($x,"sum","No data to reduce"));// string(17) "No data to reduce"?>
See Also
array_filter() - Filters elements of an array using a callback function
array_map() - Applies the callback to the elements of the given arrays
array_unique() - Removes duplicate values from an array
array_count_values() - Counts all the values of an array