How to remove subarrays based on duplicate element in subarray?

Question

How can I check and remove duplicates from the array based on ProductReference?

This is my array:

Which do you want to preserve? the first occurrence or last occurrence? — mickmackusa, Jul 10 '17 at 07:37
`array_unique($array,SORT_REGULAR)` should work for this (since the subarrays are identical), but as @MartinKuchyňár says this is better done at the database layer by using better queries. — apokryfos, Jul 10 '17 at 07:47

mickmackusa · Answer 1 · 2017-07-10T07:58:44.497

This one-liner will overwrite earlier subarrays when a new duplicate subarray is found: (Demo)

$array=array_values(array_column($array,null,"ProductReference"));

This two-liner will retain earlier subarrays and discard later ones: (Demo)

$rekeyed=array_column(array_reverse($array),null,"ProductReference");
sort($rekeyed);

apokryfos has identified the shortest/sweetest method to retain earlier subarrays and remove later ones: (Demo)

$array=array_unique($array,SORT_REGULAR);
// if the keys are important wrap array_unique() with array_values()

score 2 · Answer 2 · answered Jul 10 '17 at 07:33

2

Make the unique value your key:

$newArray = array();
foreach($oldArray as $product){
    $newArray[$product['ProductReference']] = $product;
}

answered Jul 10 '17 at 07:33

verhie

1,298
1
7
7

The new array will not have numeric keys. This process will overwrite earlier subarrays with later subarrays. – mickmackusa Jul 10 '17 at 08:00

score 1 · Answer 3 · answered Jul 10 '17 at 07:32

This may solve your problem or guide you.You can remove duplicate based on any key.Yes if you can make in database query go for that, that will be better. Directly copied from php manual

<?php 
$details = array( 
    0 => array("id"=>"1", "name"=>"Mike",    "num"=>"9876543210"), 
    1 => array("id"=>"2", "name"=>"Carissa", "num"=>"08548596258"), 
    2 => array("id"=>"1", "name"=>"Mathew",  "num"=>"784581254"), 
); 

function unique_multidim_array($array, $key) { 
    $temp_array = array(); 
    $i = 0; 
    $key_array = array(); 

    foreach($array as $val) { 
        if (!in_array($val[$key], $key_array)) { 
            $key_array[$i] = $val[$key]; 
            $temp_array[$i] = $val; 
        } 
        $i++; 
    } 
    return $temp_array; 
} 

$details = unique_multidim_array($details,'id'); 
var_dump($details);

output

$details = array( 
    0 => array("id"=>"1","name"=>"Mike","num"=>"9876543210"), 
    1 => array("id"=>"2","name"=>"Carissa","num"=>"08548596258"), 
);

How to remove subarrays based on duplicate element in subarray?

3 Answers3