Introduction

The Collection class in the Datatype package provides a set of convenient methods for working with arrays. It implements ArrayAccess, IteratorAggregate, and Countable interfaces, which allows you to use it like an array. Here you can see its API and see how to use it.

Usage

You can make a new instance of this class and use it as an array or use the available methods on the class:

$collection = new Collection([1 => 'John', 2 => 'Jane']);

// Use as array
foreach ($collection as $number => $item) {
    echo $number . ' ' . $item . ','; // Output: 1 John,2 Jane
}

echo count($collection); // Output: 2

// Use items() method on the object
foreach ($collection->items() as $number => $item) {
    echo $number . ' ' . $item . ','; // Output: 1 John,2 Jane
}

echo count($collection->items()); // Output: 2

Methods

Here you can see a list of the available methods on the collection:

count

This method returns the number of items in the collection.

public function count(): int

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
assert_true(2 === $collection->count());

each

The each method can get used to run a closure against each item of the collection. The each method always passes the value as the first argument and the key as the second argument to the given closure.

public function each(Closure $closure): static

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
$collection->each(function ($value, $key) {
    echo $key . ' ' . $value . PHP_EOL;
});

// Output:
1 John
2 Jane

every

Signature

public function every(Closure $check = null): bool

Definition

This method checks whether all items in the collection pass the provided check closure. If no closure is provided, it returns true if all items are truthy.

Examples

echo (int) new Collection(['foo', 'bar', 'baz'])->every(fn ($item) => is_string($item)); // Output: 1
echo (int) new Collection(['foo', 'bar', 'baz'])->every(fn ($item, $key) => is_numeric($key)); // Output: 1
echo (int) new Collection(['foo', 'bar', 'baz'])->every(fn ($item, $key) => strlen($item) > 3); // Output: 0
echo (int) new Collection([1, 2, 3])->every(); // Output: 1
echo (int) new Collection(['foo', 'bar', 'baz'])->every(); // Output: 1
echo (int) new Collection([null, 0, '', []])->every(); // Output: 0

---

except

This method returns a new collection containing all items that don't pass the provided check closure. If no closure is provided, it returns all items that are falsy.

public function except(Closure $check = null): static

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
$result = $collection->except(function ($value, $key) {
    return $value === 'John';
});
var_dump($result);

// Output:
array(1) {
  [2]=>
  string(4) "Jane"
}

filter

This method returns a new collection containing all items that pass the provided filter closure. If no closure is provided, it returns all items that are truthy.

public function filter(Closure $closure = null): static

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
$result = $collection->filter(function ($value, $key) {
    return $value === 'John';
});
var_dump($result);

// Output:
array(1) {
  [1]=>
  string(4) "John"
}

first_key

Signature

public function first_key(Closure $condition = null): string|int|null

Definition

This method returns the key of the first item in the collection that passes the provided condition closure. If no closure is provided, it returns the first key of the collection. If the collection is empty, it returns null.

Examples

echo new Collection(['foo' => 1, 'bar' => 2, 'baz' => 2])->first_key(fn ($item, $key) => $item === 2); // Output: 'bar'
echo new Collection(['foo', 'baz'])->first_key(); // Output: 0
assert_true(null === new Collection([null => 'foo', 'foo' => 'bar'])->first_key());
echo new Collection([1 => 'bar', 'foo' => 'baz'])->first_key(); // Output: 1
echo new Collection('foo' => ['bar'], 'bar' => 'baz')->first_key(); // Output: 'foo'
assert_true(null === new Collection([])->first_key());

first

Signature

public function first(Closure $condition = null): mixed

Definition

This method returns the first item in the collection that passes the provided condition closure. If no closure is provided, it returns the first item of the collection. If the collection is empty, it returns null.

Examples

assert_true('bar' === new Collection(['foo', 'bar', 'baz'])->first(fn ($item, $key) => Str\first_character($item) === 'b'));
assert_true('foo' === new Collection(['foo', 'baz'])->first());
assert_true(null === new Collection([null, 'foo'])->first());
assert_true(1 === new Collection([1, 'foo'])->first());
assert_true(['bar'] === new Collection(['bar'], 'foo')->first());
assert_true(null === new Collection([])->first());

forget

This method removes all items from the collection that pass the provided condition closure, and returns the collection object. It does nothing when the check returns null for items.

public function forget(Closure $condition): static

Example

$collection = new Collection([1 => 'foo', 2 => 'bar', 3 => 'baz']);
$collection->forget(fn ($item, $key) => $item === 'foo' || $key === 2);
assert_true([3 => 'baz'] === $collection->items());

$collection = new Collection([1 => 'foo', 2 => 'bar']);
$collection->forget(fn ($item, $key) => $item === 'hello worlds');
assert_true([1 => 'foo', 2 => 'bar'] === $collection->items());

// Output:
array(1) {
  [2]=>
  string(4) "Jane"
}

has

Signature

public function has(Closure $closure): bool

Definition

This method checks whether the collection contains any items that pass the provided closure. It returns true if at least one item passes the closure, and false otherwise.

Examples

assert_true(new Collection(['foo' => 'bar', 'baz' => 'qux'])->has(fn ($item, $key) => $item === 'qux'));
assert_true(new Collection(['foo' => 'bar', 'baz' => 'qux'])->has(fn ($item, $key) => $key === 'baz'));
assert_false(new Collection(['foo' => 'bar', 'baz' => 'qux'])->has(fn ($item, $key) => $key === 0));
assert_false(new Collection(['foo' => 'bar', 'baz' => 'qux'])->has(fn ($item, $key) => $item === null));

items

Signature

public function items(): array

Definition

This method returns the underlying array of the collection.

Examples

$collection = new Collection(['foo' => 'bar', 'baz' => 'qux'];
assert_true(['foo' => 'bar', 'baz' => 'qux'] === $collection->items());

keys

This method returns the keys of the underlying array of the collection.

public function keys(): array

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
var_dump($collection->keys());

// Output:
array(2) {
  [0]=>
  int(1)
  [1]=>
  int(2)
}

last_key

Signature

public function last_key(Closure $condition = null): string|int|null

Definition

This method returns the key of the last item in the collection that passes the provided condition closure. If no closure is provided, it returns the last key of the collection. If the collection is empty, it returns null.

Examples

assert_true('baz' === new Collection(['foo' => 1, 'bar' => 2, 'baz' => 2])->last_key(fn ($item, $key) => $item === 2));
assert_true(null === new Collection([])->last_key());
assert_true(1 === new Collection(['foo', 'baz'])->last_key());
assert_true('' === new Collection(['foo' => 'bar', null => 'foo'])->last_key());
assert_true(1 === new Collection(['foo' => 'baz', 1 => 'bar'])->last_key());
assert_true('foo' === new Collection(['bar' => 'baz', 'foo' => ['bar']])->last_key());

last

Signature

public function last(Closure $condition = null): mixed

Definition

This method returns the last item in the collection that passes the provided condition closure. If no closure is provided, it returns the last item of the collection. If the collection is empty, it returns null.

Examples

assert_true('baz' === new Collection(['foo', 'bar', 'baz'])->last(fn ($item, $key) => first_character($item) === 'b'));
assert_true('baz' === new Collection(['foo', 'baz'])->last());
assert_true(null === new Collection(['foo', null])->last());
assert_true(1 === new Collection(['foo', 1])->last());
assert_true(['bar'] === new Collection(['foo', ['bar']])->last());
assert_true(null === new Collection([])->last())

map

Signature

public function map(Closure $closure): array

Definition

This method applies the provided closure to each item in the collection and returns an array of the results.

Examples

$collection = new Collection(['foo', 'bar', 'baz']);

assert_true(['0foo', '1bar', '2baz'] === $collection->map(fn ($item, $key) => $key.$item));

push

This method adds the provided value to the end of the collection.

public function push(mixed $value): static

Example

$collection = new Collection([1 => 'foo', 2 => 'bar']);
$collection->push('baz');

assert_true([1 => 'foo', 2 => 'bar', 'baz'] === $collection->items());

put

This method adds the provided value to the collection at the provided key. If no key is provided, the value is added to the array by natural key.

public function put(mixed $value, int|string|null $key = null): static

Example

$collection = new Collection([1 => 'foo', 2 => 'bar']);
$collection->put('baz', 3);
assert_true([1 => 'foo', 2 => 'bar', 3 => 'baz'] === $collection->items());

$collection = new Collection([1 => 'foo', 2 => 'bar']);
$collection->put('baz');

assert_true([1 => 'foo', 2 => 'bar', 'baz'] === $collection->items());

reduce

This method applies the provided closure to each item in the collection and returns a single value. The closure takes 3 arguments: the carry value, the current item, and the current key. It works just like the array_reduce function. If no carry passed, the initial carry sets as null.

public function reduce(Closure $closure, mixed $carry = null): mixed

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
$result = $collection->reduce(function ($carry, $value) {
    return $value === 'Jane' || $carry;
}, false);

var_dump($result); // Output: bool(true)

skip

The skip method returns a new collection by skipping the specified number of elements from the beginning of the given collection.

public function skip(int $offset): static

Example

$collection = new Collection(['foo', 'bar', 'baz']);

assert_true(['foo', 'bar', 'baz'] === $collection->skip(0)->items());
assert_true(['bar', 'baz'] === $collection->skip(1)->items());
assert_true(['baz'] === $collection->skip(2)->items());
assert_true([] === $collection->skip(3)->items());

take

This method returns the first item in the collection that passes the provided condition closure and removes it from the collection. If no item passes the condition, it returns null.

public function take(Closure $condition): mixed

Example

$collection = new Collection(['foo', 'bar', 'baz']);
$result = $collection->take(fn ($item, $key) => $item === 'bar');
assert_true('bar' === $result);
assert_true([0 => 'foo', 2 => 'baz'] === $collection->items());

$collection = new Collection(['foo', 'bar', 'baz']);
$result = $collection->take(fn ($item, $key) => $item === 'qux');
assert_true(null === $result);
assert_true([0 => 'foo', 1 => 'bar', 2 => 'baz'] === $collection->items());

values

This method returns an array of the values in the collection.

public function values(): array

Example

$collection = new Collection([1 => 'John', 2 => 'Jane']);
var_dump($collection->values());

// Output:
array(2) {
  [0]=>
  string(4) "John"
  [1]=>
  string(4) "Jane"
}