Class Collection

Constructor. You can provide an array or any traversable object

Parameters

Throws

Returns an array that can be used to describe the internal state of this object.

Returns

Returns an array for serializing this of this object.

Returns

Rebuilds the Collection instance.

Parameters

Returns

Returns a callable that receives a value and will return whether it matches certain condition.

Parameters

Returns

Returns a column from $data that can be extracted by iterating over the column names contained in $path. It will return arrays for elements in represented with {*}

Parameters

Returns

Returns a callable that can be used to extract a property or column from an array or object based on a dot separated path.

Parameters

Returns

Returns a column from $data that can be extracted by iterating over the column names contained in $path

Parameters

Returns

Returns a new collection as the result of concatenating the list of elements in this collection with the passed list of elements

Parameters

Returns

Append a single item creating a new collection.

Parameters

Returns

Returns the average of all the values extracted with $path or of this collection.

Example:

$items = [
 ['invoice' => ['total' => 100]],
 ['invoice' => ['total' => 200]]
];

$total = (new Collection($items))->avg('invoice.total');

// Total: 150

$total = (new Collection([1, 2, 3]))->avg();
// Total: 2

The average of an empty set or 0 rows is null. Collections with null values are not considered empty.

Parameters

Returns

Returns a new collection where the operations performed by this collection. No matter how many times the new collection is iterated, those operations will only be performed once.

This can also be used to make any non-rewindable iterator rewindable.

Returns

Create a new collection that is the cartesian product of the current collection

In order to create a cartesian product a collection must contain a single dimension of data.

Example

$collection = new Collection([['A', 'B', 'C'], [1, 2, 3]]);
$result = $collection->cartesianProduct()->toArray();
$expected = [
    ['A', 1],
    ['A', 2],
    ['A', 3],
    ['B', 1],
    ['B', 2],
    ['B', 3],
    ['C', 1],
    ['C', 2],
    ['C', 3],
];

Parameters

Returns

Throws

Breaks the collection into smaller arrays of the given size.

Example:

$items [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
$chunked = (new Collection($items))->chunk(3)->toList();
// Returns [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11]]

Parameters

Returns

Breaks the collection into smaller arrays of the given size.

Example:

$items ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5, 'f' => 6];
$chunked = (new Collection($items))->chunkWithKeys(3)->toList();
// Returns [['a' => 1, 'b' => 2, 'c' => 3], ['d' => 4, 'e' => 5, 'f' => 6]]

Parameters

Returns

Returns a new collection where the values extracted based on a value path and then indexed by a key path. Optionally this method can produce parent groups based on a group property path.

Examples:

$items = [
 ['id' => 1, 'name' => 'foo', 'parent' => 'a'],
 ['id' => 2, 'name' => 'bar', 'parent' => 'b'],
 ['id' => 3, 'name' => 'baz', 'parent' => 'a'],
];

$combined = (new Collection($items))->combine('id', 'name');

// Result will look like this when converted to array
[
 1 => 'foo',
 2 => 'bar',
 3 => 'baz',
];

$combined = (new Collection($items))->combine('id', 'name', 'parent');

// Result will look like this when converted to array
[
 'a' => [1 => 'foo', 3 => 'baz'],
 'b' => [2 => 'bar'],
];

Parameters

Returns

Iterates once all elements in this collection and executes all stacked operations of them, finally it returns a new collection with the result. This is useful for converting non-rewindable internal iterators into a collection that can be rewound and used multiple times.

A common use case is to re-use the same variable for calculating different data. In those cases it may be helpful and more performant to first compile a collection and then apply more operations to it.

Example:

$collection->map($mapper)->sortBy('age')->extract('name');
$compiled = $collection->compile();
$isJohnHere = $compiled->some($johnMatcher);
$allButJohn = $compiled->filter($johnMatcher);

In the above example, had the collection not been compiled before, the iterations for map, sortBy and extract would've been executed twice: once for getting $isJohnHere and once for $allButJohn

You can think of this method as a way to create save points for complex calculations in a collection.

Parameters

Returns

Returns true if $value is present in this collection. Comparisons are made both by value and type.

Parameters

Returns

Returns the amount of elements in the collection.

WARNINGS:

Will change the current position of the iterator:

Calling this method at the same time that you are iterating this collections, for example in a foreach, will result in undefined behavior. Avoid doing this.

Consumes all elements for NoRewindIterator collections:

On certain type of collections, calling this method may render unusable afterwards. That is, you may not be able to get elements out of it, or to iterate on it anymore.

Specifically any collection wrapping a Generator (a function with a yield statement) or a unbuffered database cursor will not accept any other function calls after calling count() on it.

Create a new collection with buffered() method to overcome this problem.

Can report more elements than unique keys:

Any collection constructed by appending collections together, or by having internal iterators returning duplicate keys, will report a larger amount of elements using this functions than the final amount of elements when converting the collections to a keyed array. This is because duplicate keys will be collapsed into a single one in the final array, whereas this count method is only concerned by the amount of elements after converting it to a plain list.

If you need the count of elements after taking the keys in consideration (the count of unique keys), you can call countKeys()

Returns

Sorts a list into groups and returns a count for the number of elements in each group. Similar to groupBy, but instead of returning a list of values, returns a count for the number of values in that group.

When $callback is a string it should be a property name to extract or a dot separated path of properties that should be followed to get the last one in the path.

Example:

$items = [
 ['id' => 1, 'name' => 'foo', 'parent_id' => 10],
 ['id' => 2, 'name' => 'bar', 'parent_id' => 11],
 ['id' => 3, 'name' => 'baz', 'parent_id' => 10],
];

$group = (new Collection($items))->countBy('parent_id');

// Or
$group = (new Collection($items))->countBy(function ($e) {
 return $e['parent_id'];
});

// Result will look like this when converted to array
[
 10 => 2,
 11 => 1
];

Parameters

Returns

Returns the number of unique keys in this iterator. This is the same as the number of elements the collection will contain after calling toArray()

This method comes with a number of caveats. Please refer to CollectionInterface::count() for details.

Returns

Applies a callback to the elements in this collection.

Example:

$collection = (new Collection($items))->each(function ($value, $key) {
 echo "Element $key: $value";
});

Parameters

Returns

Returns true if all values in this collection pass the truth test provided in the callback.

The callback is passed the value and key of the element being tested and should return true if the test passed.

Example:

$overTwentyOne = (new Collection([24, 45, 60, 15]))->every(function ($value, $key) {
 return $value > 21;
});

Empty collections always return true.

Parameters

Returns

Returns a new collection containing the column or property value found in each of the elements.

The matcher can be a string with a property name to extract or a dot separated path of properties that should be followed to get the last one in the path.

If a column or property could not be found for a particular element in the collection, that position is filled with null.

Example:

Extract the user name for all comments in the array:

$items = [
    ['comment' => ['body' => 'cool', 'user' => ['name' => 'Mark']]],
    ['comment' => ['body' => 'very cool', 'user' => ['name' => 'Renan']]],
];
$extracted = (new Collection($items))->extract('comment.user.name');

// Result will look like this when converted to array
['Mark', 'Renan']

It is also possible to extract a flattened collection out of nested properties

 $items = [
     ['comment' => ['votes' => [['value' => 1], ['value' => 2], ['value' => 3]]],
     ['comment' => ['votes' => [['value' => 4]],
];
$extracted = (new Collection($items))->extract('comment.votes.{*}.value');

// Result will contain
[1, 2, 3, 4]

Parameters

Returns

Looks through each value in the collection, and returns another collection with all the values that pass a truth test. Only the values for which the callback returns true will be present in the resulting collection.

Each time the callback is executed it will receive the value of the element in the current iteration, the key of the element and this collection as arguments, in that order.

Example:

Filtering odd numbers in an array, at the end only the value 2 will be present in the resulting collection:

$collection = (new Collection([1, 2, 3]))->filter(function ($value, $key) {
 return $value % 2 === 0;
});

Parameters

Returns

Returns the first result in this collection

Returns

Returns the first result matching all the key-value pairs listed in conditions.

Parameters

Returns

Splits a collection into sets, grouped by the result of running each value through the callback. If $callback is a string instead of a callable, groups by the property named by $callback on each of the values.

When $callback is a string it should be a property name to extract or a dot separated path of properties that should be followed to get the last one in the path.

Example:

$items = [
 ['id' => 1, 'name' => 'foo', 'parent_id' => 10],
 ['id' => 2, 'name' => 'bar', 'parent_id' => 11],
 ['id' => 3, 'name' => 'baz', 'parent_id' => 10],
];

$group = (new Collection($items))->groupBy('parent_id');

// Or
$group = (new Collection($items))->groupBy(function ($e) {
 return $e['parent_id'];
});

// Result will look like this when converted to array
[
 10 => [
     ['id' => 1, 'name' => 'foo', 'parent_id' => 10],
     ['id' => 3, 'name' => 'baz', 'parent_id' => 10],
 ],
 11 => [
     ['id' => 2, 'name' => 'bar', 'parent_id' => 11],
 ]
];

Parameters

Returns

Given a list and a callback function that returns a key for each element in the list (or a property name), returns an object with an index of each item. Just like groupBy, but for when you know your keys are unique.

When $callback is a string it should be a property name to extract or a dot separated path of properties that should be followed to get the last one in the path.

Example:

$items = [
 ['id' => 1, 'name' => 'foo'],
 ['id' => 2, 'name' => 'bar'],
 ['id' => 3, 'name' => 'baz'],
];

$indexed = (new Collection($items))->indexBy('id');

// Or
$indexed = (new Collection($items))->indexBy(function ($e) {
 return $e['id'];
});

// Result will look like this when converted to array
[
 1 => ['id' => 1, 'name' => 'foo'],
 3 => ['id' => 3, 'name' => 'baz'],
 2 => ['id' => 2, 'name' => 'bar'],
];

Parameters

Returns

Returns a new collection containing each of the elements found in $values as a property inside the corresponding elements in this collection. The property where the values will be inserted is described by the $path parameter.

The $path can be a string with a property name or a dot separated path of properties that should be followed to get the last one in the path.

If a column or property could not be found for a particular element in the collection as part of the path, the element will be kept unchanged.

Example:

Insert ages into a collection containing users:

$items = [
    ['comment' => ['body' => 'cool', 'user' => ['name' => 'Mark']]],
    ['comment' => ['body' => 'awesome', 'user' => ['name' => 'Renan']]],
];
$ages = [25, 28];
$inserted = (new Collection($items))->insert('comment.user.age', $ages);

// Result will look like this when converted to array
[
    ['comment' => ['body' => 'cool', 'user' => ['name' => 'Mark', 'age' => 25]]],
    ['comment' => ['body' => 'awesome', 'user' => ['name' => 'Renan', 'age' => 28]]]
];

Parameters

Returns

Returns whether there are elements in this collection

Example:

$items [1, 2, 3];
(new Collection($items))->isEmpty(); // false

(new Collection([]))->isEmpty(); // true

Returns

Returns the data that can be converted to JSON. This returns the same data as toArray() which contains only unique keys.

Part of JsonSerializable interface.

Returns

Returns the last result in this collection

Returns

Returns a new collection where any operations chained after it are guaranteed to be run lazily. That is, elements will be yielded one at a time.

A lazy collection can only be iterated once. A second attempt results in an error.

Returns

Returns a new collection with each of the elements of this collection after flattening the tree structure. The tree structure is defined by nesting elements under a key with a known name. It is possible to specify such name by using the '$nestingKey' parameter.

By default all elements in the tree following a Depth First Search will be returned, that is, elements from the top parent to the leaves for each branch.

It is possible to return all elements from bottom to top using a Breadth First Search approach by passing the '$dir' parameter with 'asc'. That is, it will return all elements for the same tree depth first and from bottom to top.

Finally, you can specify to only get a collection with the leaf nodes in the tree structure. You do so by passing 'leaves' in the first argument.

The possible values for the first argument are aliases for the following constants and it is valid to pass those instead of the alias:

• desc: RecursiveIteratorIterator::SELF_FIRST
• asc: RecursiveIteratorIterator::CHILD_FIRST
• leaves: RecursiveIteratorIterator::LEAVES_ONLY

Example:

$collection = new Collection([
 ['id' => 1, 'children' => [['id' => 2, 'children' => [['id' => 3]]]]],
 ['id' => 4, 'children' => [['id' => 5]]]
]);
$flattenedIds = $collection->listNested()->extract('id'); // Yields [1, 2, 3, 4, 5]

Parameters

Returns

Returns another collection after modifying each of the values in this one using the provided callable.

Each time the callback is executed it will receive the value of the element in the current iteration, the key of the element and this collection as arguments, in that order.

Example:

Getting a collection of booleans where true indicates if a person is female:

$collection = (new Collection($people))->map(function ($person, $key) {
 return $person->gender === 'female';
});

Parameters

Returns

Looks through each value in the list, returning a Collection of all the values that contain all of the key-value pairs listed in $conditions.

Example:

$items = [
    ['comment' => ['body' => 'cool', 'user' => ['name' => 'Mark']]],
    ['comment' => ['body' => 'very cool', 'user' => ['name' => 'Renan']]],
];

$extracted = (new Collection($items))->match(['user.name' => 'Renan']);

// Result will look like this when converted to array
[
    ['comment' => ['body' => 'very cool', 'user' => ['name' => 'Renan']]],
]

Parameters

Returns

Returns the top element in this collection after being sorted by a property. Check the sortBy method for information on the callback and $sort parameters

Examples:

// For a collection of employees
$max = $collection->max('age');
$max = $collection->max('user.salary');
$max = $collection->max(function ($e) {
 return $e->get('user')->get('salary');
});

// Display employee name
echo $max->name;

Parameters

Returns

Returns the median of all the values extracted with $path or of this collection.

Example:

$items = [
 ['invoice' => ['total' => 400]],
 ['invoice' => ['total' => 500]]
 ['invoice' => ['total' => 100]]
 ['invoice' => ['total' => 333]]
 ['invoice' => ['total' => 200]]
];

$total = (new Collection($items))->median('invoice.total');

// Total: 333

$total = (new Collection([1, 2, 3, 4]))->median();
// Total: 2.5

The median of an empty set or 0 rows is null. Collections with null values are not considered empty.

Parameters

Returns

Returns the bottom element in this collection after being sorted by a property. Check the sortBy method for information on the callback and $sort parameters

Examples:

// For a collection of employees
$min = $collection->min('age');
$min = $collection->min('user.salary');
$min = $collection->min(function ($e) {
 return $e->get('user')->get('salary');
});

// Display employee name
echo $min->name;

Parameters

Returns

Returns a new collection where the values are nested in a tree-like structure based on an id property path and a parent id property path.

Parameters

Returns

Returns a new collection.

Allows classes which use this trait to determine their own type of returned collection interface

Parameters

Returns

Unwraps this iterator and returns the simplest traversable that can be used for getting the data out

Returns

Prepend a set of items to a collection creating a new collection

Parameters

Returns

Prepend a single item creating a new collection.

Parameters

Returns

Folds the values in this collection to a single value, as the result of applying the callback function to all elements. $initial is the initial state of the reduction, and each successive step of it should be returned by the callback function. If $initial is omitted the first value of the collection will be used in its place and reduction will start from the second item.

Parameters

Returns

Looks through each value in the collection, and returns another collection with all the values that do not pass a truth test. This is the opposite of filter.

Each time the callback is executed it will receive the value of the element in the current iteration, the key of the element and this collection as arguments, in that order.

Example:

Filtering even numbers in an array, at the end only values 1 and 3 will be present in the resulting collection:

$collection = (new Collection([1, 2, 3]))->reject(function ($value, $key) {
 return $value % 2 === 0;
});

Parameters

Returns

Returns a new collection with maximum $length random elements from this collection

Parameters

Returns

Returns a new collection with the elements placed in a random order, this function does not preserve the original keys in the collection.

Returns

Returns a new collection that will skip the specified amount of elements at the beginning of the iteration.

Parameters

Returns

Returns true if any of the values in this collection pass the truth test provided in the callback.

The callback is passed the value and key of the element being tested and should return true if the test passed.

Example:

$hasYoungPeople = (new Collection([24, 45, 15]))->some(function ($value, $key) {
 return $value < 21;
});

Parameters

Returns

Returns a sorted iterator out of the elements in this collection, ranked based on the results of applying a callback function to each value. The parameter $path can also be a string representing the column or property name.

The callback will receive as its first argument each of the elements in $items, the value returned by the callback will be used as the value for sorting such element. Please note that the callback function could be called more than once per element.

Example:

$items = $collection->sortBy(function ($user) {
 return $user->age;
});

// alternatively
$items = $collection->sortBy('age');

// or use a property path
$items = $collection->sortBy('department.name');

// output all user name order by their age in descending order
foreach ($items as $user) {
 echo $user->name;
}

Parameters

Returns

Creates a new collection that when iterated will stop yielding results if the provided condition evaluates to true.

This is handy for dealing with infinite iterators or any generator that could start returning invalid elements at a certain point. For example, when reading lines from a file stream you may want to stop the iteration after a certain value is reached.

Example:

Get an array of lines in a CSV file until the timestamp column is less than a date

$lines = (new Collection($fileLines))->stopWhen(function ($value, $key) {
 return (new DateTime($value))->format('Y') < 2012;
})
->toArray();

Get elements until the first unapproved message is found:

$comments = (new Collection($comments))->stopWhen(['is_approved' => false]);

Parameters

Returns

Returns the total sum of all the values extracted with $matcher or of this collection.

Example:

$items = [
 ['invoice' => ['total' => 100]],
 ['invoice' => ['total' => 200]],
];

$total = (new Collection($items))->sumOf('invoice.total');

// Total: 300

$total = (new Collection([1, 2, 3]))->sumOf();
// Total: 6

Parameters

Returns

Returns a new collection with maximum $length elements in the internal order this collection was created. If a second parameter is passed, it will determine from what position to start taking elements.

Parameters

Returns

Returns the last N elements of a collection

Example:

$items = [1, 2, 3, 4, 5];

$last = (new Collection($items))->takeLast(3);

// Result will look like this when converted to array
[3, 4, 5];

Parameters

Returns

Passes this collection through a callable as its first argument. This is useful for decorating the full collection with another object.

Example:

$items = [1, 2, 3];
$decorated = (new Collection($items))->through(function ($collection) {
     return new MyCustomCollection($collection);
});

Parameters

Returns

Returns an array representation of the results

Parameters

Returns

Returns an numerically-indexed array representation of the results. This is equivalent to calling toArray(false)

Returns

Transpose rows and columns into columns and rows

Example:

$items = [
      ['Products', '2012', '2013', '2014'],
      ['Product A', '200', '100', '50'],
      ['Product B', '300', '200', '100'],
      ['Product C', '400', '300', '200'],
]

$transpose = (new Collection($items))->transpose()->toList();

// Returns
// [
//     ['Products', 'Product A', 'Product B', 'Product C'],
//     ['2012', '200', '300', '400'],
//     ['2013', '100', '200', '300'],
//     ['2014', '50', '100', '200'],
// ]

Returns

Throws

Creates a new collection where the items are the concatenation of the lists of items generated by the transformer function applied to each item in the original collection.

The transformer function will receive the value and the key for each of the items in the collection, in that order, and it must return an array or a Traversable object that can be concatenated to the final result.

If no transformer function is passed, an "identity" function will be used. This is useful when each of the elements in the source collection are lists of items to be appended one after another.

Example:

$items [[1, 2, 3], [4, 5]];
$unfold = (new Collection($items))->unfold(); // Returns [1, 2, 3, 4, 5]

Using a transformer

$items [1, 2, 3];
$allItems = (new Collection($items))->unfold(function ($page) {
 return $service->fetchPage($page)->toArray();
});

Parameters

Returns

Loops through each value in the collection and returns a new collection with only unique values based on the value returned by the callback.

The callback is passed the value as the first argument and the key as the second argument.

Parameters

Returns

Returns the closest nested iterator that can be safely traversed without losing any possible transformations. This is used mainly to remove empty IteratorIterator wrappers that can only slowdown the iteration process.

Returns

Combines the elements of this collection with each of the elements of the passed iterables, using their positional index as a reference.

Example:

$collection = new Collection([1, 2]);
$collection->zip([3, 4], [5, 6])->toList(); // returns [[1, 3, 5], [2, 4, 6]]

Parameters

Returns

Combines the elements of this collection with each of the elements of the passed iterables, using their positional index as a reference.

The resulting element will be the return value of the $callable function.

Example:

$collection = new Collection([1, 2]);
$zipped = $collection->zipWith([3, 4], [5, 6], function (...$args) {
  return array_sum($args);
});
$zipped->toList(); // returns [9, 12]; [(1 + 3 + 5), (2 + 4 + 6)]

Parameters

Returns