Ex : Display category wise products in tableview

Display grouped data into UITableView or UICollectionView

//Datasource
 var categories:[String : [Product]] = [
        "Category 1": [
            Product(pTitle: "Product 1", pRate: "45"),
            Product(pTitle: "Product 2", pRate: "55"),
        ],
        "Category 2": [
            Product(pTitle: "Product 3", pRate: "3"),
            Product(pTitle: "Product 4", pRate: "33"),
        ],
       
    ]

 // tableview methods 
   override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return self.categories?.count ?? 0
    }
    
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return (categories[Array(categories.keys)[section]]?.count)!
    }
    
    override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return Array(categories.keys)[section]
    }
    
    override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let headerFrame = tableView.frame
        
        let title = UILabel()
        title.frame = (section == 0) ? CGRectMake(10, 10, 200, 20) : CGRectMake(10, 10, 200, 20)
        title.font = title.font.fontWithSize(14)
        title.text = self.tableView(tableView, titleForHeaderInSection: section)?.uppercaseString
        title.textColor = EditFile.categoryTextColor
        
        let headerView:UIView = UIView(frame: CGRectMake(0, 0, headerFrame.size.width, headerFrame.size.height))
        headerView.addSubview(title)
        
        return headerView
    }
    
    override func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 40
    }
    
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("productCell", forIndexPath: indexPath) as! ProductsTableCell
      
        let section = Array(categories.keys)[indexPath.section]
        let prod:Product = categories[section]![indexPath.row]
        cell.productNameLabel.text = prod.pTitle
        cell.productPriceLabel.text = prod.pTitle
        return cell
    }