var arrData = [String]() // This is your data array
var arrSelectedIndex = [IndexPath]() // This is selected cell Index array
var selectedSkills = [String]() // This is selected cell data array

extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource
{
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return arrData.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell : CollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewCell", for: indexPath) as! CollectionViewCell
          if selectedSkills.contains(arrData[indexPath.row]) {
            cell.skillsView.backgroundColor = cell.skillsView.hexStringToUIColor(hex: "FEDA22")
        }
      return cell
    }
  
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        print("You selected cell #\(indexPath.item)!")
        
            if let cell = collectionView.cellForItem(at: indexPath) as? SkillsCollectionViewCell {

                let selectedCategory = subCategoriesPopUpArray[indexPath.item]

                if selectedSubCategories.contains(selectedCategory) {
                    cell.skillsView.backgroundColor = cell.skillsView.hexStringToUIColor(hex: "F0F0F0")
                    selectedSubCategories = selectedSubCategories.filter {
                        $0 != selectedCategory
                    }
                } else {
                    selectedSubCategories.append(selectedCategory)
                    cell.skillsView.backgroundColor = cell.skillsView.hexStringToUIColor(hex: "FEDA22")
                }
        }
    }
}