Htykuut

$array1 = array("$name1" => "$id1");



$array2 = array("$name2" => "$id2", "$name3" => "$id3");

I need a new array combining all together, i.e. it would be

$array3 = array("$name1" => "$id1", "$name2" => "$id2", "$name3" => "$id3");

What is the best way to do this?

Sorry, I forgot, the ids will never match each other, but technically the names could, yet would not be likely, and they all need to be listed in one array. I looked at array_merge but wasn't sure if that was best way to do this. Also, how would you unit test this?

array_merge() is more efficient but there are a couple of options:

$array1 = array("id1" => "value1");



$array2 = array("id2" => "value2", "id3" => "value3", "id4" => "value4");



$array3 = array_merge($array1, $array2/*, $arrayN, $arrayN*/);

$array4 = $array1 + $array2;



echo '<pre>';

var_dump($array3);

var_dump($array4);

echo '</pre>';





// Results:

    array(4) {

      ["id1"]=>

      string(6) "value1"

      ["id2"]=>

      string(6) "value2"

      ["id3"]=>

      string(6) "value3"

      ["id4"]=>

      string(6) "value4"

    }

    array(4) {

      ["id1"]=>

      string(6) "value1"

      ["id2"]=>

      string(6) "value2"

      ["id3"]=>

      string(6) "value3"

      ["id4"]=>

      string(6) "value4"

    }

Check out array_merge().

$array3 = array_merge($array1, $array2);

Another option is array_replace, where an original array is modified by other arrays:

• Same keys will cause subsequent values to overrite the original array


• New keys on subsequent arrays will be created on the original array

This means that the key => value association is preserved and no duplicate keys are inserted.

I use a wrapper around array_merge to deal with SeanWM's comment about null arrays; I also sometimes want to get rid of duplicates. I'm also generally wanting to merge one array into another, as opposed to creating a new array. This ends up as:

/**

 * Merge two arrays - but if one is blank or not an array, return the other.

 * @param $a array First array, into which the second array will be merged

 * @param $b array Second array, with the data to be merged

 * @param $unique boolean If true, remove duplicate values before returning

 */

function arrayMerge(&$a, $b, $unique = false) {

    if (empty($b)) {

        return;  // No changes to be made to $a

    }

    if (empty($a)) {

        $a = $b;

        return;

    }

    $a = array_merge($a, $b);

    if ($unique) {

        $a = array_unique($a);

    }

}

I stumbled upon this question trying to identify a clean way to join two assoc arrays.

I was trying to join two different tables that didn't have relationships to each other.

This is what I came up with for PDO Query joining two Tables. Samuel Cook is what identified a solution for me with the array_merge() +1 to him.

        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        $sql = "SELECT * FROM ".databaseTbl_Residential_Prospects."";

        $ResidentialData = $pdo->prepare($sql);

        $ResidentialData->execute(array($lapi));

        $ResidentialProspects = $ResidentialData->fetchAll(PDO::FETCH_ASSOC);



        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        $sql = "SELECT * FROM ".databaseTbl_Commercial_Prospects."";

        $CommercialData = $pdo->prepare($sql);

        $CommercialData->execute(array($lapi));

        $CommercialProspects = $CommercialData->fetchAll(PDO::FETCH_ASSOC);



        $Prospects = array_merge($ResidentialProspects,$CommercialProspects);

        echo '<pre>';

        var_dump($Prospects);

        echo '</pre>';

Maybe this will help someone else out.

I know it's an old question but I'd like to add one more case I had recently with MongoDB driver queries and none of array_merge, array_replace nor array_push worked. I had a bit complex structure of objects wrapped as arrays in array:

$a = [

 ["a" => [1, "a2"]],

 ["b" => ["b1", 2]]

];

$t = [

 ["c" => ["c1", "c2"]],

 ["b" => ["b1", 2]]

];

And I needed to merge them keeping the same structure like this:

$merged = [

 ["a" => [1, "a2"]],

 ["b" => ["b1", 2]],

 ["c" => ["c1", "c2"]],

 ["b" => ["b1", 2]]

];

The best solution I came up with was this:

public static function glueArrays($arr1, $arr2) {

    // merges TWO (2) arrays without adding indexing. 

    $myArr = $arr1;

    foreach ($arr2 as $arrayItem) {

        $myArr = $arrayItem;

    }

    return $myArr;

}