CODEWITHSUNDEEP
phparraysmappinglookuparray-map
kalle
kalle

Reputation: 223

Add column to 2d array mapped from a flat associative lookup array

I have an associative array of counts with brand_slug keys and a 2d array to which I would like to append related count data.

$countArray = [
    "abu-garcia" => 1,
    "daiwa" => 4,
    "shimano" => 4
];

$dataArray = [
    [
        "brand_id" => 36,
        "brand_name" => "Abu Garcia",
        "brand_slug" => "abu-garcia"
    ],
    [
        "brand_id" => 41,
        "brand_name" => "Daiwa",
        "brand_slug" => "daiwa"
    ],
    [
        "brand_id" => 41,
        "brand_name" => "Daiwa",
        "brand_slug" => "daiwa"
    ],
    [
        "brand_id" => 39,
        "brand_name" => "Shimano",
        "brand_slug" => "shimano"
    ],
    [
        "brand_id" => 39,
        "brand_name" => "Shimano",
        "brand_slug" => "shimano"
    ],
];

I want to create a new array which should look like this:

[
    [
        "brand_id" => 36,
        "brand_name" => "Abu Garcia",
        "brand_slug" => "abu-garcia",
        "count" => 1
    ],
    [
        "brand_id" => 41,
        "brand_name" => "Daiwa",
        "brand_slug" => "daiwa",
        "count" => 4,
    ],
    [
        "brand_id" => 41,
        "brand_name" => "Daiwa",
        "brand_slug" => "daiwa",
        "count" => 4
    ],
    [
        "brand_id" => 39,
        "brand_name" => "Shimano",
        "brand_slug" => "shimano",
        "count" => 4
    ],
    [
        "brand_id" => 39,
        "brand_name" => "Shimano",
        "brand_slug" => "shimano",
        "count" => 4
    ],
];

Upvotes: -2

Views: 1065

Answers (4)

mickmackusa
mickmackusa

Reputation: 48073

The task of adding a new column to all rows in a 2d array based on an associative lookup/mapping array is most elegantly done with array_map() and the array union operator (+).

Code: (Demo)

var_export(
    array_map(
        fn($row) => $row + ['count' => $countArray[$row['brand_slug']]],
        $dataArray
    )
);

There is also nothing wrong with modifying the data array by reference in a classic foreach() loop . (Demo)

foreach ($dataArray as &$row) {
    $row['count'] = $countArray[$row['brand_slug']];
}
var_export($dataArray);

As a consideration not presented in the asker's sample data, if a row's value is not found in the mapping array, use the null coalescing operator to fallback to a default value.

['count' => $countArray[$row['brand_slug']] ?? $someDefault]

Or

$row['count'] = $countArray[$row['brand_slug']] ?? $someDefault;

Upvotes: 0

user6830821
user6830821

Reputation:

array_merge Merges the elements of one or more arrays together so that the values of one are appended to the end of the previous one. It returns the resulting array.

Example #array_merge() example

<?php
$array1 = array("color" => "red", 2, 4);
$array2 = array("a", "b", "color" => "green", "shape" => "trapezoid", 4);
$result = array_merge($array1, $array2);
print_r($result);
?>

Upvotes: -1

Maya Shah
Maya Shah

Reputation: 970

In a simplest way you can do like this. Suppose your first array name is $first_array and second one is $second_array.

just loop the second one like 

foreach($second_array as $index => $item)
{
    $second_array[$index]['count'] = $first_array[$item['brand_slug']];
}

echo "<pre>";
print_r($second_array);

Upvotes: 0

JustBaron
JustBaron

Reputation: 2347

I think I understand what you're trying to do...

If these are examples of your arrays:

$CountArray = array("abu-garcia"=>1,
                "daiwa"=>4,
                "shimano"=>4);
$DataArray = array(
            array("brand_id"=>36, "brand_name"=>"Abu Garcia", "brand_slug"=>"abu-garcia"),
            array("brand_id"=>41, "brand_name"=>"Daiwa", "brand_slug"=>"daiwa"),
            array("brand_id"=>39, "brand_name"=>"Shimano", "brand_slug"=>"shimano")
);

Then loop through your second array to build a new array, and adding the count key from the first array like this:

$i = 0;
foreach($DataArray as $ItemArray){
    foreach($ItemArray as $Key=>$Value){
        $NewArray[$i][$Key] = $Value;
        $NewArray[$i]['count'] = 0;
        if(isset($CountArray[$ItemArray['brand_slug']])){
            $NewArray[$i]['count'] = $CountArray[$ItemArray['brand_slug']];         
        }
    }
    ksort($NewArray[$i]);
    $i++;
}
print_r($NewArray);

Upvotes: 1

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