Merge array where duplicate in multidimensional array

Question

I've been trying to merge this array ONLY WHERE $array[4] exists more than one time, example: $array[4] == 'red' exactly twice. How can I merge only those arrays while keeping the others? I have made several attempts at this and I am willing to include my efforts if asked.

Consider this array:

array(3) {
  [0]=>
     array(5) {
               [0]=>
                 string(3) "UID"
               [1]=>
                 string(3) "532"
               [2]=>
                 string(1) "2"
               [3]=>
                 string(9) "Domain(s)"
               [4]=>
                 string(20) "red"
             }
 [1]=>
    array(5) {
             [0]=>
                string(3) "UID"
             [1]=>
                string(3) "532"
             [2]=>
                string(7) "License"
             [3]=>
                string(3) "Fee"
             [4]=>
                string(20) "red"
            }
 [2]=>
     array(5) {
               [0]=>
                 string(3) "UID"
               [1]=>
                 string(3) "536"
               [2]=>
                 string(7) "License"
               [3]=>
                 string(3) "Fee"
               [4]=>
                 string(16) " University Test"
             }
    }

TRYING TO ACHIEVE:

    array(3) {
  [0]=>
     array(5) {
               [0]=>
                 string(3) "UID"
               [1]=>
                 string(3) "532"
               [2]=>
                 string(1) "2"
               [3]=>
                 string(9) "Domain(s)"
               [4]=>
                 string(20) " red"
               [5]=>
                 string(3) "Fee"
               [6]=>
                 string(7) "License"
             }
 [1]=>
     array(5) {
               [0]=>
                 string(3) "UID"
               [1]=>
                 string(3) "536"
               [2]=>
                 string(7) "License"
               [3]=>
                 string(3) "Fee"
               [4]=>
                 string(16) " University Test"
             }
    }

You'd get the key of the duplicate then would remove it using the key. You'd be left with a gap in the key but you'd use array_values to reorganize the keys. — Script47
– Script47, Commented Aug 14, 2015 at 21:28

Don't Panic · Accepted Answer · 2015-08-14 21:55:09Z

1

foreach ($test as $item) {
    if (!isset($merged[$item[4]])) {
        // add the item to the merged array using key=$item[4]
        $merged[$item[4]] = $item;
    } else {
         // merge the item with the item that is already in the array at key=$item[4]
         $merged[$item[4]] = array_unique(array_merge($merged[$item[4]], $item));
         // array_unique is necessary because array_merge will not overwrite numeric keys
    }
}
// convert the keys back to numeric (if you care to)
$merged = array_values($merged);

answered Aug 14, 2015 at 21:55

Don't Panic

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1 Comment

Kisaragi Over a year ago

This. Worked. Thanks mate. Didn't know you could array_unique(array_merge))!

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