Sections

Collection


Overview

Phalcon\Collection is an object oriented array. It offers speed, as well as implementations of various PHP interfaces. These are:

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

Constructor

You can construct the object as any other object in PHP. However, the constructor accepts an optional array parameter, which will populate the object for you.

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

Case sensitivity

When instantiating the object you can specify a second bool parameter, which will control the key searching in the object. By default $insensitive is set to true, making searches in the collection case insensitive. Setting this value to false will make the search for the element in a case sensitive manner.

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data, false);

echo $collection->has('COLORS'); // false

Reusing

You can also reuse the component, by repopulating it. Phalcon\Collection exposes the clear() and init() methods, which will clear and repopulate the internal array respectively,

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo $collection->count(); // 2

$data = [
    'year' => 1776,
];

$collection->clear();
$collection->init($data);

echo $collection->count(); // 1

Get

As mentioned above, Phalcon\Collection implements several interfaces, in order to make the component as flexible as possible. Retrieving data stored in an element can be done by using:

  • Property
  • __get()
  • array based get ($collection[$element])
  • offsetGet()
  • get()

The fastest way is by using the property syntax:

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo $collection->year;                    // 1776

You can use __get($element) but it is not advisable as it is much slower than the property syntax. The same applies to offsetGet

echo $collection->__get('year');           // 1776
echo $collection['year'];                  // 1776
echo $collection->offsetGet('year');       // 1776
echo $collection->get('year', 1776, true); // 1776
public function get(
    string $element, 
    mixed $defaultValue = null, 
    string $cast = null
):  mixed

Using get() offers three extra parameters. When $defaultValue is defined in the call and the element is not found, $defaultValue will be returned. The cast parameter accepts a string that defines what the returned value will be casted. The available values are:

  • array
  • bool
  • boolean
  • double
  • float
  • int
  • integer
  • null
  • object
  • string

The collection object also offers two more getters getKeys and getValues getKeys( bool $insensitive = true ) returns all the keys stored internally in the collection. By default, it will return the keys case insensitive manner i.e. all lowercase. If false is passed in the call, it will return the keys exactly as they have been stored. getValues returns the values stored in the internal collection.

Has

To check whether an element exists or not in the collection, you can use the following:

  • isset() on the property
  • __isset()
  • array based isset (isset($coollection[$element]))
  • offsetExists()
  • has()

The fastest way is by using the property syntax:

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo isset($collection->year); // true

You can use __isset(element) but it is not advisable as it is much slower than the property syntax. The same applies to offsetExists

echo $collection->__isset('year');        // true
echo isset($collection['year']);          // true
echo $collection->offsetExists('year');   // true
echo $collection->has('year', true);      // true
public function has(string $element):  bool

Set

To set an element in the collection, you can use the following:

  • assign the value to the property
  • __set()
  • array based assignment
  • offsetSet()
  • set()

The fastest way is by using the property syntax:

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
];

$collection = new Collection($data);

$collection->year = 1776;

You can use __set($element, $value) but it is not advisable as it is much slower than the property syntax. The same applies to offsetSet

$collection->__set('year', 1776);
$collection['year'] = 1776;
$collection->offsetSet('year', 1776);
$collection->set('year', 1776); 

Remove

To remove an element in the collection, you can use the following:

  • unset the property
  • __unset()
  • array based unset
  • offsetUnset()
  • remove()

The fastest way is by using the property syntax:

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
];

$collection = new Collection($data);

unset($collection->year);

You can use __unset($element) but it is not advisable as it is much slower than the property syntax. The same applies to offsetUnset

$collection->__unset('year');
unset($collection['year']);
$collection->offsetUnset('year');
$collection->remove('year'); 
public function remove(string $element):  void

Iteration

Since the collection object implements \IteratorAggregate, you can iterate through the object with ease. The method getIterator() returns an ArrayIterator() object

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

foreach ($collection as $key => $value) {
    echo $key . ' - ' . $value . PHP_EOL;
}

Count

The implementation of the \Countable interface exposes the count() method, which stores the number of elements in the collection.

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo $collection->count();    // 2

Serialization

The \Serializable and \JsonSerializable interfaces expose methods that allow you to serialize and unserialize the object. serialize() and unserialize() use PHP’s serialize and unserialize functions. jsonSerialize() returns an array which can be used with json_encode to serialize the object.

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo $collection->serialize();    // a:2:{s:6:"colors";a:3:{i:0;s:3:"red";i:1;s:5:"white";i:2;s:4:"blue";}s:4:"year";i:1776;}

$serialized = 'a:2:{s:6:"colors";a:3:{i:0;s:3:"red";i:1;s:5:"white";i:2;s:4:"blue";}s:4:"year";i:1776;}';
$collection->unserialize($serialized);

echo $collection->jsonSerialize(); // $data

Transformations

Phalcon\Collection also exposes two transformation methods: toArray() and toJson(int $options). toArray() returns the object transformed as an array. This method returns the same array as jsonSerialize().

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo $collection->toArray();  // $data

toJson(int $options) returns a JSON representation of the object. It uses json_encode internally and accepts a parameter, which represents the flags that json_encode accepts. By default the options are set up with the value 74, (RFC4327) which translates to:

  • JSON_HEX_TAG
  • JSON_HEX_APOS
  • JSON_HEX_AMP
  • JSON_HEX_QUOT
  • JSON_UNESCAPED_SLASHES

You can pass any valid flags to the method according to your needs.

<?php

use Phalcon\Collection;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new Collection($data);

echo $collection->toJson();    // ["red","white","blue"],"year":1776}

echo $collection->toJson(74 + JSON_PRETTY_PRINT);
/**
{
    "colors": [
        "red",
        "white",
        "blue"
    ],
    "year": 1776
}
*/

Read Only

Phalcon also offers a component that can be used in a read-only fashion. Phalcon\Collection\ReadOnly can serve as a collection in your application that can only be populated with initial data but not allowing its contents to be changed throughout the application.

<?php

use Phalcon\Collection\ReadOnly;

$data = [
    'colors' => [
        'red',
        'white',
        'blue',
    ],
    'year'   => 1776,
];

$collection = new ReadOnly($data);

echo $collection->toJson();    // ["red","white","blue"],"year":1776}

$collection->set('colors', ['red']); // Exception