Fill array n-in-n values in PHP - php

Question

For instance, I have an array with N elements, and I need that it have M elements where M is multiple of O. Example:
[signature: array array_fill_multiple(array, int o, mixed filler = null)]
$array = [ 1, 2 ];
array_fill_multiple($array, 1); // => [ 1, 2 ]
array_fill_multiple($array, 2); // => [ 1, 2 ]
array_fill_multiple($array, 3); // => [ 1, 2, null ]
array_fill_multiple($array, 4); // => [ 1, 2, null, null ]
$array = [ 1, 2, 3 ];
array_fill_multiple($array, 1); // => [ 1, 2, 3 ]
array_fill_multiple($array, 2); // => [ 1, 2, 3, null ]
array_fill_multiple($array, 3); // => [ 1, 2, 3 ]
array_fill_multiple($array, 4); // => [ 1, 2, 3, null ]
$array = [ 1, 2, 3, 4 ];
array_fill_multiple($array, 5, 0); // => [ 1, 2, 3, 4, 0 ]
I can do it with a for, but I guess that using native methods are possible, are not?
Edit
To explain better what I want, it need result in an array with multiples of O elements. So if I like that this array contains multiples of 5, it need result in an array with 0, 5, 10, 15, 20, 25... elements (zero included, if empty).
If my array have 15 elements, and I expect multiple of 2, it'll fit to next multiple of 2 after or equal 15, or be, 16. So only 1 padding will be created.
If my array have 3 elements and I expect multiple of 5, it'll fit to next multiple of 5, after or equal to 3, or be, the own 5. So 2 paddings will be created.
If my array have 10 elements and I expect multiple of 10, it'll fit to next multiple of 10, after or igual to 10, or be, the own 10. So none padding will be created, because my array yet is multiple of 10.
If my array is empty, it'll return an empty array.
I guess that array_pad() will help. Just need calculate the second argument to know what is the next multiple of O based on array count.

Answer 1

Something like this
$a = [1, 2, 3];
$multiple = 5;
$size = sizeof($a);
// first way
var_dump(array_pad($a, ceil($size / $multiple) * $multiple, null));
// second way
var_dump(array_pad($a, $size + ($size % $multiple ? $multiple - $size % $multiple : 0), null));
Second one is more accurate than first one. Let's suppose that you have array with 10000000000000001 items (on 64 system). Now you have to pad with multiplier 11.
$size = 10000000000000001 * 11;
$multiple = 11;
var_dump($size);
// int(110000000000000011)
// first way
ini_set('precision', 18);
var_dump(ceil($size / $multiple) * $multiple);
// double(110000000000000000)
// second way
var_dump($size + ($size % $multiple ? $multiple - $size % $multiple : 0));
// int(110000000000000011)
Now you see that first way produces wrong value because float values has less precision than int.

Answer 2

Basically you just replace "array_fill_multiple" with "array_pad" and it'll work :)
$array = [ 1, 2 ];
array_pad($array, 1, null); // => [ 1, 2 ]
array_pad($array, 2, null); // => [ 1, 2 ]
array_pad($array, 3, null); // => [ 1, 2, null ]
array_pad($array, 4, null); // => [ 1, 2, null, null ]
$array = [ 1, 2, 3 ];
array_pad($array, 1, null); // => [ 1, 2, 3 ]
array_pad($array, 2, null); // => [ 1, 2, 3, null ]
array_pad($array, 3, null); // => [ 1, 2, 3 ]
array_pad($array, 4, null); // => [ 1, 2, 3, null ]
$array = [ 1, 2, 3, 4 ];
array_pad($array, 5, 0); // => [ 1, 2, 3, 4, 0 ]