Interface CollectionInterface

Describes the methods a Collection should implement. A collection is an immutable list of elements exposing a number of traversing and extracting method for generating other collections.

Namespace: Cake\Collection

Method Summary

append() public

Returns a new collection as the result of concatenating the list of elements in this collection with the passed list of elements
buffered() public

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.
chunk() public

Breaks the collection into smaller arrays of the given size.
combine() public

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.
compile() public

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.
contains() public

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

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.
each() public

Executes the passed callable for each of the elements in this collection and passes both the value and key for them on each step. Returns the same collection for chaining.
every() public

Returns true if all values in this collection pass the truth test provided in the callback.
extract() public

Returns a new collection containing the column or property value found in each of the elements, as requested in the $matcher param.
filter() public

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.
first() public

Returns the first result in this collection
firstMatch() public

Returns the first result matching all of the key-value pairs listed in conditions.
groupBy() public

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.
indexBy() public

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.
insert() public

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.
isEmpty() public

Returns whether or not there are elements in this collection
jsonSerialize() public

Convert a result set into JSON.
last() public

Returns the last result in this collection
listNested() public

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.
map() public

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

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.
max() public

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

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

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.
reduce() public

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

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.
sample() public

Returns a new collection with maximum $size random elements from this collection
shuffle() public

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

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

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

Returns a sorted iterator out of the elements in this collection, ranked in ascending order by the results of running each value through a callback. $callback can also be a string representing the column or property name.
stopWhen() public

Creates a new collection that when iterated will stop yielding results if the provided condition evaluates to false.
sumOf() public

Returns the total sum of all the values extracted with $matcher or of this collection.
take() public

Returns a new collection with maximum $size 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.
through() public

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

Returns an array representation of the results
toList() public

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

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.
unwrap() public

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.
zip() public

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

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

Method Detail

append() ¶ public

append(arrayTraversable $items): Cake\Collection\CollectionInterface

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

Parameters

arrayTraversable $items: Items list.

Returns

Cake\Collection\CollectionInterface

buffered() ¶ public

buffered(): Cake\Collection\CollectionInterface

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

Cake\Collection\CollectionInterface

chunk() ¶ public

chunk(int $chunkSize): Cake\Collection\CollectionInterface

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

int $chunkSize: The maximum size for each chunk

Returns

Cake\Collection\CollectionInterface

combine() ¶ public

combine(callable|string $keyPath, callable|string $valuePath, callable|string|null $groupPath = null): Cake\Collection\CollectionInterface

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

callable|string $keyPath: the column name path to use for indexing or a function returning the indexing key out of the provided element
callable|string $valuePath: the column name path to use as the array value or a function returning the value out of the provided element
callable|string|null $groupPath optional: the column name path to use as the parent grouping key or a function returning the key out of the provided element

Returns

Cake\Collection\CollectionInterface

compile() ¶ public

compile(bool $preserveKeys = true): Cake\Collection\CollectionInterface

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

bool $preserveKeys optional: whether to use the keys returned by this collection as the array keys. Keep in mind that it is valid for iterators to return the same key for different elements, setting this value to false can help getting all items if keys are not important in the result.

Returns

Cake\Collection\CollectionInterface

contains() ¶ public

contains(mixed $value): bool

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

Parameters

mixed $value: The value to check for

Returns

bool

countBy() ¶ public

countBy(callable|string $callback): Cake\Collection\CollectionInterface

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

callable|string $callback: the callback or column name to use for indexing or a function returning the indexing key out of the provided element

Returns

Cake\Collection\CollectionInterface

each() ¶ public

each(callable $c): Cake\Collection\CollectionInterface

Executes the passed callable for each of the elements in this collection and passes both the value and key for them on each step. Returns the same collection for chaining.

Example:

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

Parameters

callable $c: callable function that will receive each of the elements in this collection

Returns

Cake\Collection\CollectionInterface

every() ¶ public

every(callable $c): bool

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

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

Example:

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

Parameters

callable $c: a callback function

Returns

bool

extract() ¶ public

extract(string $matcher): Cake\Collection\CollectionInterface

Returns a new collection containing the column or property value found in each of the elements, as requested in the $matcher param.

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

string $matcher: a dot separated string symbolizing the path to follow inside the hierarchy of each value so that the column can be extracted.

Returns

Cake\Collection\CollectionInterface

filter() ¶ public

filter(callable|null $c = null): Cake\Collection\CollectionInterface

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

callable|null $c optional: the method that will receive each of the elements and returns true whether or not they should be in the resulting collection. If left null, a callback that filters out falsey values will be used.

Returns

Cake\Collection\CollectionInterface

first() ¶ public

first(): mixed

Returns the first result in this collection

Returns

mixed

firstMatch() ¶ public

firstMatch(array $conditions): mixed

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

Parameters

array $conditions: a key-value list of conditions where the key is a property path as accepted by Collection::extract, and the value the condition against with each element will be matched

Returns

mixed

groupBy() ¶ public

groupBy(callable|string $callback): Cake\Collection\CollectionInterface

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

callable|string $callback: the callback or column name to use for grouping or a function returning the grouping key out of the provided element

Returns

Cake\Collection\CollectionInterface

indexBy() ¶ public

indexBy(callable|string $callback): Cake\Collection\CollectionInterface

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

callable|string $callback: the callback or column name to use for indexing or a function returning the indexing key out of the provided element

Returns

Cake\Collection\CollectionInterface

insert() ¶ public

insert(string $path, mixed $values): Cake\Collection\CollectionInterface

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

string $path: a dot separated string symbolizing the path to follow inside the hierarchy of each value so that the value can be inserted
mixed $values: The values to be inserted at the specified path, values are matched with the elements in this collection by its positional index.

Returns

Cake\Collection\CollectionInterface

isEmpty() ¶ public

isEmpty(): bool

Returns whether or not there are elements in this collection

Example:

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

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

Returns

bool

jsonSerialize() ¶ public

jsonSerialize(): array

Convert a result set into JSON.

Part of JsonSerializable interface.

Returns

array

last() ¶ public

last(): mixed

Returns the last result in this collection

Returns

mixed

listNested() ¶ public

listNested(string|int $dir = 'desc', string|callable $nestingKey = 'children'): Cake\Collection\CollectionInterface

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: TreeIterator::SELF_FIRST
asc: TreeIterator::CHILD_FIRST
leaves: TreeIterator::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

string|int $dir optional: The direction in which to return the elements
string|callable $nestingKey optional: The key name under which children are nested or a callable function that will return the children list

Returns

Cake\Collection\CollectionInterface

map() ¶ public

map(callable $c): Cake\Collection\CollectionInterface

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

callable $c: the method that will receive each of the elements and returns the new value for the key that is being iterated

Returns

Cake\Collection\CollectionInterface

match() ¶ public

match(array $conditions): Cake\Collection\CollectionInterface

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

array $conditions: a key-value list of conditions where the key is a property path as accepted by `Collection::extract, and the value the condition against with each element will be matched

Returns

Cake\Collection\CollectionInterface

max() ¶ public

max(callable|string $callback, int $type = SORT_NUMERIC): mixed

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

callable|string $callback: the callback or column name to use for sorting
int $type optional: the type of comparison to perform, either SORT_STRING SORT_NUMERIC or SORT_NATURAL

Returns

mixed

min() ¶ public

min(callable|string $callback, int $type = SORT_NUMERIC): mixed

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

callable|string $callback: the callback or column name to use for sorting
int $type optional: the type of comparison to perform, either SORT_STRING SORT_NUMERIC or SORT_NATURAL

Returns

mixed

nest() ¶ public

nest(callable|string $idPath, callable|string $parentPath): Cake\Collection\CollectionInterface

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

callable|string $idPath: the column name path to use for determining whether an element is parent of another
callable|string $parentPath: the column name path to use for determining whether an element is child of another

Returns

Cake\Collection\CollectionInterface

reduce() ¶ public

reduce(callable $c, mixed $zero = null): void

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

Parameters

callable $c: The callback function to be called
mixed $zero optional: The state of reduction

Returns

void

reject() ¶ public

reject(callable $c): Cake\Collection\CollectionInterface

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

callable $c: the method that will receive each of the elements and returns true whether or not they should be out of the resulting collection.

Returns

Cake\Collection\CollectionInterface

sample() ¶ public

sample(int $size = 10): Cake\Collection\CollectionInterface

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

Parameters

int $size optional: the maximum number of elements to randomly take from this collection

Returns

Cake\Collection\CollectionInterface

shuffle() ¶ public

shuffle(): Cake\Collection\CollectionInterface

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

Returns

Cake\Collection\CollectionInterface

skip() ¶ public

skip(int $howMany): Cake\Collection\CollectionInterface

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

Parameters

int $howMany: The number of elements to skip.

Returns

Cake\Collection\CollectionInterface

some() ¶ public

some(callable $c): bool

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

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

Example:

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

Parameters

callable $c: a callback function

Returns

bool

sortBy() ¶ public

sortBy(callable|string $callback, int $dir = SORT_DESC, int $type = SORT_NUMERIC): Cake\Collection\CollectionInterface

Returns a sorted iterator out of the elements in this collection, ranked in ascending order by the results of running each value through a callback. $callback 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

callable|string $callback: the callback or column name to use for sorting
int $dir optional: either SORT_DESC or SORT_ASC
int $type optional: the type of comparison to perform, either SORT_STRING SORT_NUMERIC or SORT_NATURAL

Returns

Cake\Collection\CollectionInterface

stopWhen() ¶ public

stopWhen(callable $condition): Cake\Collection\CollectionInterface

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

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

callable $condition: the method that will receive each of the elements and returns false when the iteration should be stopped. If an array, it will be interpreted as a key-value list of conditions where the key is a property path as accepted by Collection::extract, and the value the condition against with each element will be matched.

Returns

Cake\Collection\CollectionInterface

sumOf() ¶ public

sumOf(string|callable|null $matcher = null): float|int

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

string|callable|null $matcher optional: The property name to sum or a function If no value is passed, an identity function will be used. that will return the value of the property to sum.

Returns

float|int

take() ¶ public

take(int $size = 1, int $from = 0): Cake\Collection\CollectionInterface

Returns a new collection with maximum $size 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

int $size optional: the maximum number of elements to take from this collection
int $from optional: A positional offset from where to take the elements

Returns

Cake\Collection\CollectionInterface

through() ¶ public

through(callable $handler): Cake\Collection\CollectionInterface

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

callable $handler: A callable function that will receive this collection as first argument.

Returns

Cake\Collection\CollectionInterface

toArray() ¶ public

toArray(bool $preserveKeys = true): array

Returns an array representation of the results

Parameters

bool $preserveKeys optional: whether to use the keys returned by this collection as the array keys. Keep in mind that it is valid for iterators to return the same key for different elements, setting this value to false can help getting all items if keys are not important in the result.

Returns

array

toList() ¶ public

toList(): array

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

Returns

array

unfold() ¶ public

unfold(callable|null $transformer = null): Cake\Collection\CollectionInterface

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

callable|null $transformer optional: A callable function that will receive each of the items in the collection and should return an array or Traversable object

Returns

Cake\Collection\CollectionInterface

unwrap() ¶ public

unwrap(): Iterator

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

Iterator

zip() ¶ public

zip(arrayTraversable $items): Cake\Collection\CollectionInterface

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

arrayTraversable $items: The collections to zip.

Returns

Cake\Collection\CollectionInterface

zipWith() ¶ public

zipWith(arrayTraversable $items, callable $callable): Cake\Collection\CollectionInterface

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 () {
  return array_sum(func_get_args());
});
$zipped->toList(); // returns [9, 12]; [(1 + 3 + 5), (2 + 4 + 6)]

Parameters

arrayTraversable $items: The collections to zip.
callable $callable: The function to use for zipping the elements together.

Returns

Cake\Collection\CollectionInterface

Namespaces

Interface CollectionInterface

Method Summary

append() public

buffered() public

chunk() public

combine() public

compile() public

contains() public

countBy() public

each() public

every() public

extract() public

filter() public

first() public

firstMatch() public

groupBy() public

indexBy() public

insert() public

isEmpty() public

jsonSerialize() public

last() public

listNested() public

map() public

match() public

max() public

min() public

nest() public

reduce() public

reject() public

sample() public

shuffle() public

skip() public

some() public

sortBy() public

stopWhen() public

sumOf() public

take() public

through() public

toArray() public

toList() public

unfold() public

unwrap() public

zip() public

zipWith() public

Method Detail

append() ¶ public

Parameters

Returns

buffered() ¶ public

Returns

chunk() ¶ public

Example:

Parameters

Returns

combine() ¶ public

Examples:

Parameters

Returns

compile() ¶ public

Example:

Parameters

Returns

contains() ¶ public

Parameters

Returns

countBy() ¶ public

Example:

Parameters

Returns

each() ¶ public

Example:

Parameters

Returns

every() ¶ public

Example:

Parameters

Returns

extract() ¶ public

Example: