PHP remove duplicate arrays inside a multi dimensional array

Question

I need to check the 2D array($arr) for any duplicates(order does not matter) and put them into a clean array.

For example:

$arr = array ( 
    array (-9,1,8 ), 
    array (-9,2,7 ),
    array (-9,3,6 ),
    array (-9,4,5 ),
    array (-9,5,4 ),
    array (-9,6,3 ),
    array (-9,7,2 ),
    array (-9,8,1 )
)

needs to be end up being:

$cleanArr = array ( 
    array (-9,1,8 ), 
    array (-9,2,7 ),
    array (-9,3,6 ),
    array (-9,4,5 )
)

or

$cleanArr =  array(     
    array (-9,5,4 ),
    array (-9,6,3 ),
    array (-9,7,2 ),
    array (-9,8,1 )
)

Is there a PHP function for this or do I need to do some sort of loop to clean out the duplicates?

Kevin · Accepted Answer · 2015-03-19 04:47:19Z

5

No function does this outright, you could use a combination of functions though. You could first sort all of sub batches of array first into ascending order first, then serialize each on them, utilize array_unique, then unserialize again to have that multi dimensional again:

foreach($arr as &$a){ sort($a); }
$arr = array_map('unserialize', array_unique(array_map('serialize', $arr)));
print_r($arr);

answered Mar 19, 2015 at 4:47

Kevin

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1 Comment

Icewine Over a year ago

Yes, this worked great. That is too bad there is no one function for this. ++ for the great work around!

Adrian Cid Almaguer · Accepted Answer · 2015-03-19 05:23:59Z

0

Try this:

    <?php

    $arr = array ( 
    array (-9,1,8 ), 
    array (-9,2,7 ),
    array (-9,3,6 ),
    array (-9,4,5 ),
    array (-9,5,4 ),
    array (-9,6,3 ),
    array (-9,7,2 ),
    array (-9,8,1 )
    );

    $arr = array_map(function($n) {return explode(',', $n);}, (array_unique(array_map(function($n) {sort($n); return implode(',', $n);}, $arr))));

echo var_export($arr, true);

?>

Output:

array (
  0 => 
  array (
    0 => '-9',
    1 => '1',
    2 => '8',
  ),
  1 => 
  array (
    0 => '-9',
    1 => '2',
    2 => '7',
  ),
  2 => 
  array (
    0 => '-9',
    1 => '3',
    2 => '6',
  ),
  3 => 
  array (
    0 => '-9',
    1 => '4',
    2 => '5',
  ),
)

answered Mar 19, 2015 at 5:23

Adrian Cid Almaguer

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