Get number of column in a colelctionView IOS

i'm a beginner in IOS. I use CollectionView in my first Appp. My problem is i can't get the number of column (or line) calculated in the collectionView. The collection view is inside a scroll view, I want to set the height of the collection view because I don't want to scroll in the collectionView but I want to see all the Items.

Is this possible?

Thanks, F.G