(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
array_fill — Fill an array with values
Fills an array with
count
entries of the value of the
value
parameter, keys starting at the
start_index
parameter.
start_index
The first index of the returned array.
If start_index
is negative,
the first index of the returned array will be
start_index
and the following
indices will start from zero prior to PHP 8.0.0;
as of PHP 8.0.0, negative keys are incremented normally
(see example).
count
Number of elements to insert.
Must be greater than or equal to zero, and less than or equal to 2147483647
.
value
Value to use for filling
Returns the filled array
Throws a ValueError if count
is
out of range.
Version | Description |
---|---|
8.0.0 |
array_fill() now throws a ValueError
if count is out of range; previously E_WARNING
was raised, and the function returned false .
|
Example #1 array_fill() example
<?php
$a = array_fill(5, 6, 'banana');
print_r($a);
?>
The above example will output:
Array ( [5] => banana [6] => banana [7] => banana [8] => banana [9] => banana [10] => banana )
Example #2 array_fill() example with a negative start index
<?php
$a = array_fill(-2, 4, 'pear');
print_r($a);
?>
Output of the above example in PHP 8:
Array ( [-2] => pear [-1] => pear [0] => pear [1] => pear )
Output of the above example in PHP 7:
Array ( [-2] => pear [0] => pear [1] => pear [2] => pear )
Note that index -1
is not present prior to PHP 8.0.0.
See also the Arrays section of manual for a detailed explanation of negative keys.
This is what I recently did to quickly create a two dimensional array (10x10), initialized to 0:
<?php
$a = array_fill(0, 10, array_fill(0, 10, 0));
?>
This should work for as many dimensions as you want, each time passing to array_fill() (as the 3rd argument) another array_fill() function.
If you need negative indices:
<?php
$b = array_fill(-2, 4, 'pear');//this is not what we want
$c = array_fill_keys(range(-2,1),'pear');//these are negative indices
print_r($b);
print_r($c);
?>
Here is result of the code above:
Array
(
[-2] => pear
[0] => pear
[1] => pear
[2] => pear
)
Array
(
[-2] => pear
[-1] => pear
[0] => pear
[1] => pear
)
Using objects with array_fill may cause unexpected results. Consider the following:
<?php
class Foo {
public $bar = "banana";
}
//fill an array with objects
$array = array_fill(0, 2, new Foo());
var_dump($array);
/*
array(2) {
[0]=>
object(Foo)#1 (1) {
["bar"]=>
string(6) "banana"
}
[1]=>
object(Foo)#1 (1) {
["bar"]=>
string(6) "banana"
}
} */
//now we change the attribute of the object stored in index 0
//this actually changes the attribute for EACH object in the ENTIRE array
$array[0]->bar = "apple";
var_dump($array);
/*
array(2) {
[0]=>
object(Foo)#1 (1) {
["bar"]=>
string(5) "apple"
}
[1]=>
object(Foo)#1 (1) {
["bar"]=>
string(5) "apple"
}
}
*/
?>
Objects are filled in the array BY REFERENCE. They are not copied for each element in the array.
As of PHP 8.0 the example code
<?php
$b = array_fill(-2, 4, 'pear');
print_r($b);
?>
now returns
Array
(
[-2] => pear
[-1] => pear
[0] => pear
[1] => pear
)
See https://wiki.php.net/rfc/negative_array_index and https://github.com/php/php-src/pull/3772
I made this function named "array_getMax" that returns te maximum value and index, from array:
<?php
//using array_search_all by helenadeus at gmail dot com
function array_search_all($needle, $haystack)
{#array_search_match($needle, $haystack) returns all the keys of the values that match $needle in $haystack
foreach ($haystack as $k=>$v) {
if($haystack[$k]==$needle){
$array[] = $k;
}
}
return ($array);
}
function array_getMax($array){
$conteo=array_count_values($array);
if( count($conteo)==1 ){//returns full array when all values are the same.
return $array;
}
arsort($array);
//$antValue=null;
$maxValue=null;
$keyValue=null;
foreach($array as $key=>$value){
if($maxValue==null){
$maxValue=$value;
$keyValue=$key;
break;
}
}
$resultSearch=array_search_all($maxValue, $array);
return array_fill_keys($resultSearch, $maxValue);
}
//example
$arreglo=array('e1'=>99,'e2'=>'99','e3'=>1,'e4'=>1,'e5'=>98);
var_dump(array_getMax($arreglo));
//output
/*
array(2) {
["e1"]=>
int(99)
["e2"]=>
int(99)
}
*/
?>
I hope some one find this usefull
Fill missing keys in a (numerically-indexed) array with a default value
<?php
function fill_missing_keys($array, $default = null, $atleast = 0)
{
return $array + array_fill(0, max($atleast, max(array_keys($array))), $default);
}
?>