PHP - How to test a multidimensional array for duplicate element values in any order

Question

I'm not sure the title really gets across what I'm asking, so here's what I'm trying to do:

I have an array of arrays with four integer elements each, ie.

Array(Array(1,2,3,4), Array(4,2,3,1), Array(18,3,22,9), Array(23, 12, 33, 55))

I basically need to remove one of the two arrays that have the same values in any order, like indices 0 and 1 in the example above.

I can do this pretty easily when there are only two elements to check, using the best answer code in this question.

My multidimensional array can have 1-10 arrays at any given time, so I can't seem to figure out the best way to process a structure like that and remove arrays that have the same numbers in any order.

Thanks so much!

Scopey · Accepted Answer · 2015-01-08 02:13:48Z

4

I've been thinking about this, and I think using a well designed closure with array_filter might be the way I'd go about this:

$matches = array();
$array = array_filter($array, function($ar) use (&$matches) {
    sort($ar);
    if(in_array($ar, $matches)) {
        return false;
    }
    $matches[] = $ar;
    return true;
});

See here for an example: http://ideone.com/Zl7tlR

Edit: $array will be your final result, ignore $matches as it's just used during the filter closure.

edited Jan 8, 2015 at 2:13

answered Jan 8, 2015 at 1:17

Scopey

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6 Comments

Scriptable Over a year ago

That looked like a great answer but I've just ran this and got the same array back?

Scopey Over a year ago

The ideone example appears to work. Can you show me what input you gave it?

Scriptable Over a year ago

Ah sorry. I must of copied it wrong, I had $ar where I should have had $array.

Spectre Over a year ago

Great answer, but I seem to be getting matches that aren't in the original array.

$array = [[11,18,22,43],[42,21,38,23],[28,33,17,32],[12,25,38,22],[11,22,43,18],[12,14,17,19],[34,23,11,32],[21,33,42,45],[1,2,8,23],[8,2,1,23]]

$matches = [[11,18,22,43],[21,23,38,42],[17,28,32,33],[12,22,25,38],[12,14,17,19],[11,23,32,34],[21,33,42,45],[1,2,8,23]]

I've worked up something that seems to give me the desired result, though I'm sure it's inefficient. I'll post it as an answer shortly.

Scopey Over a year ago

I didn't note in my answer, but $array contains the result of the filter. $matches is just used for the filter. It will actually end up containing all the matches values as well except they will be sorted.

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