CompostionalLayout-MultiSections.swift

func createLayoutDiffSection() -> UICollectionViewLayout {
        let layout = UICollectionViewCompositionalLayout { (sectionIndex: Int,
            layoutEnvironment: NSCollectionLayoutEnvironment) -> NSCollectionLayoutSection? in
            
            var columns = 1
            switch sectionIndex{
            case 1:
                columns = 3
            case 2:
                columns = 5
            default:
                columns = 1
                
            }
            
            let itemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0),
                                                  heightDimension: .fractionalHeight(1.0))
            let item = NSCollectionLayoutItem(layoutSize: itemSize)
            item.contentInsets = NSDirectionalEdgeInsets(top: 2, leading: 2, bottom: 2, trailing: 2)
            
            let groupHeight = columns == 1 ?
                NSCollectionLayoutDimension.absolute(44) :
                NSCollectionLayoutDimension.fractionalWidth(0.2)
            let groupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0),
                                                   heightDimension: groupHeight)
            let group = NSCollectionLayoutGroup.horizontal(layoutSize: groupSize, subitem: item, count: columns)
            
            let section = NSCollectionLayoutSection(group: group)
            section.contentInsets = NSDirectionalEdgeInsets(top: 20, leading: 20, bottom: 20, trailing: 20)
            return section
        }
        return layout
    }