Build a custom array in Laravel-CodePudding

I am looping the database to get a list of countries with continents.

array: [
 0 => array: [
   "country" => "BE"
   "continent" => "EU"
 1 => array: [
   "country" => "BG"
   "continent" => "EU"
 ]
...
 ]

From that result, I want to create an array that shows all the continents with the countries inside.

array:[
  0 => array: [
    "continent" => "EU"
    "countries" => [
      "country" => "BE"
      "country" => "BG"
    ]
  ]

CodePudding user response：

Suppose this is your array

 $arr = [
    [
        "country" => "BE",
        "continent" => "EU",
    ],
    [
        "country" => "BG",
        "continent" => "EU",
    ]
];

Then this returns what you expected.

collect($arr)->groupBy('continent')->mapWithKeys(function ($group, $continent) {
    return [
        'continent' => $continent,
        'countries' => $group->pluck('country')->toArray()
    ];
});

CodePudding user response：

If you need just to group countries by continent, simple way to achieve this by mapToGroups()

CodePudding user response：

You will need to some how group your results by the continent. One way to do that is to loop over the initial collection and build a new array keyed by the continent.

However, seeing that you are using Laravel just group the collection by the continent.

$countries = [
    ['country' => 'A', 'continent' => 'aa'],
    ['country' => 'B', 'continent' => 'bb'],
    ['country' => 'C', 'continent' => 'aa'],
    ['country' => 'D', 'continent' => 'aa'],
    ['country' => 'E', 'continent' => 'aa'],
    ['country' => 'F', 'continent' => 'bb'],
];

// Because my data is an array I just turn that into a collection.
// But an Eloquent query builder ->get would already return a collection.
$continents = collect($countries)->groupBy('continent');

foreach ($continents as $continent => $items) {
    echo "Countries for " . $continent . "\n";
    foreach ($items as $country) {
        echo $country['country'] . "\n";
    }
}

/**
Output: 
Countries for aa
A
C
D
E
Countries for bb
B
F
**/