Collection - Get specific keys in multidimensional arrays

[ecrmnn]

I keep coming in situations where I want to filter out specific keys in a collection based on a multidimensional array.

I've previously made a PR, but it was a breaking change when extending the functionality of the only method. I'm sure this is a great addition to Collection, but I want to discuss the naming of the method.

---

Alternative 1: Accept passing an array to filter

In Pandas you can pass an array to the filter method and it will filter out the specific columns. I don't think this would be a breaking change, but would extend the filter method.

$people = collect([
    [
        'first' => 'John',
        'last' => 'Doe',
        'name' => 'John Doe',
        'email' => 'john.doe@gmail.com',
    ],
    [
        'first' => 'Jane',
        'last' => 'Doe',
        'name' => 'Jane Doe',
        'email' => 'jane.doe@gmail.com',
    ],
]);

$people->filter(['first', 'last', 'email'])->all();

//=> [
//=>     [
//=>         'first' => 'John',
//=>         'last' => 'Doe',
//=>         'email' => 'john.doe@gmail.com',
//=>     ],
//=>     [
//=>         'first' => 'Jane',
//=>         'last' => 'Doe',
//=>         'email' => 'jane.doe@gmail.com',
//=>     ],
//=> ]

Alternative 2: Accept passing an array to map

When you have to do this manually you would use map to return a new collection with the keys you want. Passing an array to map wouldn't be a breaking change, but extend the functionality.

Alternative 3: Add columns method

Follow the naming of the array_column method. I would suggest to use columns instead of column

$people->columns(['first', 'last', 'email'])->all();

Alternative 4: Add select method

Follow the naming of Eloquent when selecting columns.

$people->select(['first', 'last', 'email'])->all();

Alternative 5: Add attributes method

$people->attributes(['first', 'last', 'email'])->all();

Alternative 6: Add properties method

$people->properties(['first', 'last', 'email'])->all();

---

So what do you think? 💁‍♂️

• filter
• columns
• select
• attributes
• properties

---

Update: Added map as an alternative
Update: Fixed typo in code example

[knutle]

Personally I think select feels most appropriate for this!

[fsrocha-dev]

Certainly Filter gets better.

[smajohusic]

Attributes feels more natural

[zotopteam]

we can use this method:

$people->map->only(['first', 'last', 'email']);

[larskoole]

The discussion is pretty old so I don't know if it's fixed already but I'm using the following code (added it to the boot method in the AppServiceProvider.php) to mimic alternative 3:

Collection::macro('columns', function ($columns) {
    if (!is_array($columns)) {
        $columns = [$columns];
    }

    return $this->map(function ($item) use ($columns) {
        $newItem = [];
        foreach ($columns as $column) {
            if (array_key_exists($column, $item)) {
                $newItem[$column] = $item[$column];
            }
        }

        return $newItem;
    });
});