basic php question

Question

Why is it not possible to call a function like this

$this->getCollection()->getSku();

And it's possible to do it with a foreach like this

foreach($this->getCollection() as $item)
$item -> getSku();
endforeach

For reference ... ( in the block folder )

public function getCollection()
{
    $model = $this->_objectManager->create('Ming\Test\Model\Test');
    $collection = $model->getCollection();

    return $collection;
}

Answer 1

Magento "Model Collection" is a collection of model. Model collection extend from php IteratorAggregate, Countable, ArrayInterface SPL interface. Here you can handle complex data. So when you create a collection you cant access like this

$this->getCollection()->getSku();

Because it's a collection of items, That's why you need to access such collection following way

foreach($this->getCollection() as $item) {
    $item -> getSku();
}

Learn more from here