\Cake\DatasourceResultSetInterface

each()

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

Returns

filter()

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

Returns

reject()

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

Returns

every()

every(callable  $c) : boolean

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

Returns

true if for all elements in this collection the provided callback returns true, false otherwise.

some()

some(callable  $c) : boolean

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

Returns

true if the provided callback returns true for any element in this collection, false otherwise

contains()

contains(mixed  $value) : boolean

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

Parameters

Returns

true if $value is present in this collection

map()

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

Returns

reduce()

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

Returns

extract()

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

Returns

max()

max(callable|string  $callback, integer  $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

Returns

The value of the top element in the collection

min()

min(callable|string  $callback, integer  $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

Returns

The value of the bottom element in the collection

avg()

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

Returns

median()

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

Returns

sortBy()

sortBy(callable|string  $callback, integer  $dir = SORT_DESC, integer  $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

Returns

groupBy()

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

Returns

indexBy()

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

Returns

countBy()

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

Returns

sumOf()

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

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

shuffle()

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

sample()

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

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

Parameters

Returns

take()

take(integer  $size = 1, integer  $from) : \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

Returns

takeLast()

takeLast(integer  $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

Returns

skip()

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

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

Parameters

Returns

match()

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

Returns

firstMatch()

firstMatch(array  $conditions) : mixed

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

Parameters

Returns

first()

first() : mixed

Returns the first result in this collection

Returns

The first value in the collection will be returned.

last()

last() : mixed

Returns the last result in this collection

Returns

The last value in the collection will be returned.

append()

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

Returns

combine()

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

Returns

nest()

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

Returns

insert()

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

Returns

toArray()

toArray(boolean  $preserveKeys = true) : array

Returns an array representation of the results

Parameters

Returns

toList()

toList() : array

Returns an numerically-indexed array representation of the results.

This is equivalent to calling toArray(false)

Returns

jsonSerialize()

jsonSerialize() : array

Convert a result set into JSON.

Part of JsonSerializable interface.

Returns

The data to convert to JSON

compile()

compile(boolean  $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

Returns

lazy()

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

buffered()

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

listNested()

listNested(string|integer  $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

Returns

stopWhen()

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

Returns

unfold()

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

Returns

through()

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

Returns

zip()

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

Returns

zipWith()

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

Returns

chunk()

chunk(integer  $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

Returns

chunkWithKeys()

chunkWithKeys(integer  $chunkSize, boolean  $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

Returns

isEmpty()

isEmpty() : boolean

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

unwrap()

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

transpose()

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

count()

count() : integer

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

countKeys()

countKeys() : integer

Returns the number of unique keys in this iterator. This is, 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