Question

How to find duplicates in an array with PHP

Answer 1

$arr = [1, 1, 4, 5, 7, 8, 7, 3, 2, 3];
 
$unique = array_unique($arr);

$duplicates = array_diff_key($arr, $unique); 
    
print_r($duplicates);




/*
run:

Array
(
    [1] => 1
    [6] => 7
    [9] => 3
)

*/

 

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Answer 2

$arr = [1, 1, 4, 5, 7, 8, 7, 7, 7, 7, 3, 2, 3];
  
$unique = array_unique($arr);
 
$duplicates = array_diff_key($arr, $unique); 
print_r($duplicates);

$unique = array_unique($duplicates);
print_r($unique);

 
 
 
 
/*
run:
 
Array
(
    [1] => 1
    [6] => 7
    [7] => 7
    [8] => 7
    [9] => 7
    [12] => 3
)
Array
(
    [1] => 1
    [6] => 7
    [12] => 3
)

*/

 

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