//bootstrap the library, it of course uses autoload because it's not 1998 anymore
require_once 'Phinq/bootstrap.php';

//fully qualifying things sucks
use Phinq\Phinq;

//suppose you have some sort of collection
$payments = array(10.5, 11.94, 9.3, 0, 17.1, 10.5, 0);

//let's do something to it
$paymentQuery = Phinq::create($payments)
  ->where(function($payment) { return $payment !== 0; }) //non-zero
  ->orderBy(function($payment) { return $payment; }); //sorted ascending

//nothing happens until we evaluate the expressions by calling toArray()
$nonZeroOrderedPayments = $paymentQuery->toArray();
print_r($nonZeroOrderedPayments);
/*
Array
(
    [0] => 9.3
    [1] => 10.5
    [2] => 10.5
    [3] => 11.94
    [4] => 17.1
)
*/

//non-zero, ordered and distinct
print_r($paymentQuery->distinct()->toArray());
/*
Array
(
    [0] => 9.3
    [1] => 10.5
    [2] => 11.94
    [3] => 17.1
)
*/

//say we had a Person struct, and each person has a place of residence
class Person {
  public $id;
  public $name;
  public $residence;
  
  public function __construct($id, $name, State $state) {
    $this->id = $id;
    $this->name = $name;
    $this->residence = $state;
  }
}

class State {
  public $id;
  public $name;
  public $region;
  public $code;
  
  public function __construct($id, $name, $region, $code) {
    $this->id = $id;
    $this->name = $name;
    $this->region = $region;
    $this->code = $code;
  }
}
  
//...and we have these people who live in these states
$people = array(
  new Person(1, 'Tommy', new State(1, 'California', 'SW', 'CA')),
  new Person(2, 'Bobby', new State(2, 'Washington', 'NW', 'WA')),
  new Person(3, 'Joey', new State(2, 'Washington', 'NW', 'WA')),
  new Person(4, 'Jerry', new State(3, 'New York', 'NE', 'NY')),
  new Person(3, 'Dubya', new State(4, 'Texas', 'S', 'TX'))
);
  
//...and we want to group them by region
echo Phinq::create($people)
  ->groupBy(function($person) { return $person->residence->region; })
  ->select(function($grouping) { 
    //$grouping is an instance of Phinq\Grouping, which inherits from Phinq
    //it has a getKey() method which returns the key used to perform the grouping
    $obj = new stdClass();
    $obj->people = $grouping;
    $obj->region = $grouping->getKey();
    return $obj;
  })->orderBy(function($obj) { return $obj->people->count(); }, true /* descending */)
  ->aggregate(function($current, $next) { 
    $count = $next->people->count();
    return $current . sprintf(
      "%d %s (%s) live in the %s region\n",
      $count,
      $count === 1 ? 'person' : 'people',
      $next->people->aggregate(function($current, $next) {
        if ($current !== null) {
          $current .= ', ';
        }
        return $current . sprintf('%s [%s]', $next->name, $next->residence->code);
      }),
      $next->region
    );
  });

/*
2 people (Bobby [WA], Joey [WA]) live in the NW region
1 person (Dubya [TX]) live in the S region
1 person (Tommy [CA]) live in the SW region
1 person (Jerry [NY]) live in the NE region
*/