Quickstart

This page provides a quick introduction to Collections and introductory examples.

If you have not already installed, Collections, head over to the installation page.

Vector

The Vector represents the List in .NET language or non-associative arrays in php:

use Collections\Vector;

$person1 = new \stdClass();
$person1->name = 'John';
$person1->age = 25;

$person2 = new \stdClass();
$person2->name = 'Maria';
$person2->age = 30;

$person3 = new \stdClass();
$person3->name = 'Anderson';
$person3->age = 15;

$collection = new Collections\Vector();
$collection->add($person1);
$collection->add($person2);
$collection->add($person3);

$collection->filter(function($person){
    return $person->age > 18;
})->each(function($item){
    echo $item->name; //John and Maria
});

Lets continue with the example above and count how many elements we have!

echo $collection->count();

Great, now we know how to run through a collection and how to count it, but these are pretty simple things to do, so lets sort them:

use Collections\Vector;
use Collections\Comparer\StringComparer;

$collection->sort(); //by default the sort is by the keys
$collection->sort(new StringComparer()); //this will sort by alfabetic order
$collection->sort(new YourCustomComparer()); //you can create your own custom comparer to sort your collection

Yeah that is great, isn't it? But we can do much more things, now lets search for someone in the collection.

print_r($collection->contains("John")); //returns true

Ok, now that we've learned the basic concepts about collections, I'll show you other type of collection called Map.

Map

The Map class is something like associative arrays in PHP, or Hash tables in other languages.

use Collections\Map;

$dictionary = new Map();
$dictionary->add('person1', array(
  'name' => 'John',
  'age' => 20
));
$dictionary->add('person2', array(
  'name' => 'Maria',
  'age' => 19
));
$dictionary->add('person3', array(
  'name' => 'Anderson',
  'age' => 25
));

$dictionary->each(function($item){
    echo $key . ": " . $item['name'] . "-" . $item['age'];
});

We can use object as keys too.

use Collections\Map;

$dictionary = new Map();

$object = new \stdClass();
$dictionary->add($object, 'value');
echo $dictionary->get($object); //prints 'value'

When one key is added we can't insert the same key again, if we want to change its value we need to use the method set(). Here is an example of how we can get some item based on the key;

  print_r ($dictionary->get('person1')); //returns ['name' => John, 'age' => 20]

Working with objects

To our last example we'll use objects in our collection.

use Collections\Vector;

$collection = new Vector();
$collection->add(new Person('John', 20));
$collection->add(new Person('Peter', 20));
$collection->add(new Person('Sophie', 21));
$collection->add(new Person('Angela', 29));
$collection->add(new Person('Maria', 19));
$collection->add(new Person('Anderson', 25));

$collection->each(function($item){
    echo $item->getName();
});

Pretty simple, but the reason I wanted to show you objects is because of Reactive Extension API. Lets seek everyone with age 20.

// this will return John and Peter
$people = $people->filter(function($person){
    return $person->getAge() === 20;
});

The map() method will create a new collection based on the output of the callback being applied to each object in the original collection:

$new = $people->map(function ($person, $key) {
    return $person->getAge() * 2;
});

// $result contains all persons with twice theirs ages;
$result = $new->toArray();