How to create fixed length multi dimensional array in php? - php

Question

int twodim[5][8];
int threedim[3][5][8];
How to create fixed length multi dimensional array in php as we create in c++ ?

Answer 1

To create fixed array you should use SplFixedArray from Standard PHP Library extension:
The SplFixedArray class provides the main functionalities of array. The main differences between a SplFixedArray and a normal PHP array is that the SplFixedArray is of fixed length and allows only integers within the range as indexes. The advantage is that it allows a faster array implementation.

Answer 2

It's not very PHP-like, but you can use this function (based on Grzegorz' SplFixedArray hint) to generate fixed sized arrays of any dimension.
function createFixedArray() {
$args = func_get_arg(0);
$array = new SplFixedArray($args[0]);
if (isset($args[1])) {
$newArgs = array_splice($args, 1);
for ($i=0; $i<$args[0]; $i++) {
$array[$i] = createFixedArray($newArgs);
}
}
return $array;
}
Example use:
$fixedArray = createFixedArray(array(2, 2, 2));
$fixedArray[0][0][0] = 0;
$fixedArray[0][0][1] = 1;
$fixedArray[0][1][0] = 1;
$fixedArray[0][1][1] = 0;
$fixedArray[1][0][0] = 1;
$fixedArray[1][0][1] = 0;
$fixedArray[1][1][0] = 0;
$fixedArray[1][1][1] = 1;
var_dump($fixedArray);
Generates
object(SplFixedArray)#1 (2) {
[0]=>
object(SplFixedArray)#2 (2) {
[0]=>
object(SplFixedArray)#3 (2) {
[0]=>
int(0)
[1]=>
int(1)
}
[1]=>
object(SplFixedArray)#4 (2) {
[0]=>
int(1)
[1]=>
int(0)
}
}
[1]=>
object(SplFixedArray)#5 (2) {
[0]=>
object(SplFixedArray)#6 (2) {
[0]=>
int(1)
[1]=>
int(0)
}
[1]=>
object(SplFixedArray)#7 (2) {
[0]=>
int(0)
[1]=>
int(1)
}
}
}