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Class NestIterator

A type of collection that is aware of nested items and exposes methods to check or retrieve them

Namespace: Cake\Collection\Iterator

Property Summary

  • $_nestKey protected
    string|callable

    The name of the property that contains the nested items for each element

Method Summary

  • __construct() public

    Constructor

  • __debugInfo() public

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

  • _createMatcherFilter() protected

    Returns a callable that receives a value and will return whether or not it matches certain condition.

  • _extract() protected

    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 {*}

  • _propertyExtractor() protected

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

  • _simpleExtract() protected

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

  • _unwrap() public deprecated

    Backwards compatible wrapper for unwrap()

  • append() public

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

  • appendItem() public

    {@inheritDoc}

  • avg() public

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

  • 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.

  • cartesianProduct() public
  • chunk() public

    Breaks the collection into smaller arrays of the given size.

  • chunkWithKeys() 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.

  • count() public

    Returns the amount of elements in the collection.

  • 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.

  • countKeys() public

    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()

  • 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.

  • getChildren() public

    Returns a traversable containing the children for the current item

  • 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.

  • hasChildren() public

    Returns true if there is an array or a traversable object stored under the configured nestKey for the current item

  • 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

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

  • last() public

    Returns the last result in this collection

  • lazy() public

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

  • 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

  • median() public

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

  • 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.

  • newCollection() protected

    Returns a new collection.

  • optimizeUnwrap() protected

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

  • prepend() public

    {@inheritDoc}

  • prependItem() public

    {@inheritDoc}

  • 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

  • serialize() public

    Returns a string representation of this object that can be used to reconstruct it

  • 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 true.

  • 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.

  • takeLast() public

    Returns the last N elements of a collection

  • 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)

  • transpose() public

    Transpose rows and columns into columns and rows

  • 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.

  • unserialize() public

    Unserializes the passed string and rebuilds the Collection instance

  • 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

__construct() ¶ public

__construct(array|Traversable $items, string|callable $nestKey)

Constructor

Parameters
array|Traversable $items

Collection items.

string|callable $nestKey

the property that contains the nested items If a callable is passed, it should return the childrens for the passed item

__debugInfo() ¶ public

__debugInfo(): array

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

Returns
array

_createMatcherFilter() ¶ protected

_createMatcherFilter(array $conditions): Closure

Returns a callable that receives a value and will return whether or not it matches certain condition.

Parameters
array $conditions

A key-value list of conditions to match where the key is the property path to get from the current item and the value is the value to be compared the item with.

Returns
Closure

_extract() ¶ protected

_extract(array|ArrayAccess $data, string[] $path): mixed

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
array|ArrayAccess $data

Data.

string[] $path

Path to extract from.

Returns
mixed

_propertyExtractor() ¶ protected

_propertyExtractor(string|callable $callback): callable

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
string|callable $callback

A dot separated path of column to follow so that the final one can be returned or a callable that will take care of doing that.

Returns
callable

_simpleExtract() ¶ protected

_simpleExtract(array|ArrayAccess $data, string[] $path): mixed

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

Parameters
array|ArrayAccess $data

Data.

string[] $path

Path to extract from.

Returns
mixed

_unwrap() ¶ public

_unwrap(): Traversable

Backwards compatible wrapper for unwrap()

Returns
Traversable

append() ¶ public

append(array|Traversable $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
array|Traversable $items
Returns
Cake\Collection\CollectionInterface

appendItem() ¶ public

appendItem(mixed $item, mixed $key = null)

{@inheritDoc}

Parameters
$item
$key optional

avg() ¶ public

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

Returns the average of all the values extracted with $matcher 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
Parameters
string|callable|null $matcher optional
Returns
float|int|null

buffered() ¶ public

buffered(): Cake\Collection\Iterator\BufferedIterator

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\Iterator\BufferedIterator

cartesianProduct() ¶ public

cartesianProduct(callable|null $operation = null, callable|null $filter = null): Cake\Collection\CollectionInterface
Parameters
callable|null $operation optional

Operation

callable|null $filter optional

Filter

Returns
Cake\Collection\CollectionInterface
Throws
LogicException

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
Returns
Cake\Collection\CollectionInterface

chunkWithKeys() ¶ public

chunkWithKeys(int $chunkSize, bool $preserveKeys = true): Cake\Collection\CollectionInterface

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
int $chunkSize
bool $preserveKeys optional
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
callable|string $valuePath
callable|string|null $groupPath optional
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
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
Returns
bool

count() ¶ public

count(): int

Returns the amount of elements in the collection.

WARNINGS:

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()

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.

Returns
int

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
Returns
Cake\Collection\CollectionInterface

countKeys() ¶ public

countKeys(): int

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
int

each() ¶ public

each(callable $c): $this

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
Returns
$this

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;
});

Empty collections always return true because it is a vacuous truth.

Parameters
callable $c
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
Returns
Cake\Collection\CollectionInterface

filter() ¶ public

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

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
Returns
Cake\Collection\Iterator\FilterIterator

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
Returns
mixed

getChildren() ¶ public

getChildren(): RecursiveIterator

Returns a traversable containing the children for the current item

Returns
RecursiveIterator

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
Returns
Cake\Collection\CollectionInterface

hasChildren() ¶ public

hasChildren(): bool

Returns true if there is an array or a traversable object stored under the configured nestKey for the current item

Returns
bool

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
Returns
Cake\Collection\CollectionInterface

insert() ¶ public

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

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
mixed $values
Returns
Cake\Collection\Iterator\InsertIterator

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

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
array

last() ¶ public

last(): mixed

Returns the last result in this collection

Returns
mixed

lazy() ¶ public

lazy(): Cake\Collection\CollectionInterface

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

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

Returns
Cake\Collection\CollectionInterface

listNested() ¶ public

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

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
string|callable $nestingKey optional
Returns
Cake\Collection\Iterator\TreeIterator

map() ¶ public

map(callable $c): Cake\Collection\Iterator\ReplaceIterator

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
Returns
Cake\Collection\Iterator\ReplaceIterator

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
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
int $type optional
Returns
mixed

median() ¶ public

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

Returns the median of all the values extracted with $matcher 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
Parameters
string|callable|null $matcher optional
Returns
float|int|null

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
int $type optional
Returns
mixed

nest() ¶ public

nest(callable|string $idPath, callable|string $parentPath, string $nestingKey = 'children'): 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
callable|string $parentPath
string $nestingKey optional
Returns
Cake\Collection\CollectionInterface

newCollection() ¶ protected

newCollection(mixed ...$args): Cake\Collection\CollectionInterface

Returns a new collection.

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

Parameters
mixed ...$args

Constructor arguments.

Returns
Cake\Collection\CollectionInterface

optimizeUnwrap() ¶ protected

optimizeUnwrap(): Traversable|array

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

Returns
Traversable|array

prepend() ¶ public

prepend(mixed $items)

{@inheritDoc}

Parameters
$items

prependItem() ¶ public

prependItem(mixed $item, mixed $key = null)

{@inheritDoc}

Parameters
$item
$key optional

reduce() ¶ public

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

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
mixed $zero optional
Returns
mixed

reject() ¶ public

reject(callable $c): Cake\Collection\Iterator\FilterIterator

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
Returns
Cake\Collection\Iterator\FilterIterator

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
Returns
Cake\Collection\CollectionInterface

serialize() ¶ public

serialize(): string

Returns a string representation of this object that can be used to reconstruct it

Returns
string

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
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
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
int $dir optional
int $type optional
Returns
Cake\Collection\CollectionInterface

stopWhen() ¶ public

stopWhen(callable $condition): Cake\Collection\Iterator\StoppableIterator

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
callable $condition
Returns
Cake\Collection\Iterator\StoppableIterator

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
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
int $from optional
Returns
Cake\Collection\CollectionInterface

takeLast() ¶ public

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

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
int $howMany
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
Returns
Cake\Collection\CollectionInterface

toArray() ¶ public

toArray(bool $preserveKeys = true): array

Returns an array representation of the results

Parameters
bool $preserveKeys optional
Returns
array

toList() ¶ public

toList(): array

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

Returns
array

transpose() ¶ public

transpose(): Cake\Collection\CollectionInterface

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
Cake\Collection\CollectionInterface
Throws
LogicException

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
Returns
Cake\Collection\CollectionInterface

unserialize() ¶ public

unserialize(string $collection): void

Unserializes the passed string and rebuilds the Collection instance

Parameters
string $collection

The serialized collection

Returns
void

unwrap() ¶ public

unwrap(): Traversable

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
Traversable

zip() ¶ public

zip(array|Traversable $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
array|Traversable $items
Returns
Cake\Collection\CollectionInterface

zipWith() ¶ public

zipWith(array|Traversable $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 = $collection->zipWith([3, 4], [5, 6], function (...$args) {
  return array_sum($args);
});
$zipped->toList(); // returns [9, 12]; [(1 + 3 + 5), (2 + 4 + 6)]
Parameters
array|Traversable $items
callable $callable
Returns
Cake\Collection\CollectionInterface

Property Detail

$_nestKey ¶ protected

The name of the property that contains the nested items for each element

Type
string|callable
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