I have a PHP array which looks like this example:
$array[0][0] = 'apples';
$array[0][1] = 'pears';
$array[0][2] = 'oranges';
$array[1][0] = 'steve';
$array[1][1] = 'bob';
And I would like to be able to produce from this a table with every possible combination of these, but without repeating any combinations (regardless of their position), so for example this would output
Array 0 Array 1
apples steve
apples bob
pears steve
pears bob
But I would like for this to be able to work with as many different arrays as possible.
In mathematics, the Cartesian Product of sets A and B is defined as the set of all ordered pairs (x, y) such that x belongs to A and y belongs to B. For example, if A = {1, 2} and B = {3, 4, 5}, then the Cartesian Product of A and B is {(1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5)}.
If X=Y, we can denote the Cartesian product of X with itself as X×X=X2. For examples, since we can represent both the x-axis and the y-axis as the set of real numbers R, we can write the xy-plane as R×R=R2.
A deck of cards The Cartesian product of these sets returns a 52-element set consisting of 52 ordered pairs, which correspond to all 52 possible playing cards.
It's just the same symbol, and definitely not the same thing: the Cartesian product is a set (of vectors), the cross product is a vector.
this is called "cartesian product", php man page on arrays http://php.net/manual/en/ref.array.php shows some implementations (in comments).
and here's yet another one:
function array_cartesian() {
$_ = func_get_args();
if(count($_) == 0)
return array(array());
$a = array_shift($_);
$c = call_user_func_array(__FUNCTION__, $_);
$r = array();
foreach($a as $v)
foreach($c as $p)
$r[] = array_merge(array($v), $p);
return $r;
}
$cross = array_cartesian(
array('apples', 'pears', 'oranges'),
array('steve', 'bob')
);
print_r($cross);
You are looking for the cartesian product of the arrays, and there's an example on the php arrays site: http://php.net/manual/en/ref.array.php
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