以下是一个简单的示例代码，演示如何按日期对照片进行分组显示的部分可滚动视图：

import UIKit

struct Photo {
    let date: String
    let image: UIImage
}

class ViewController: UIViewController {
    
    let photos = [
        Photo(date: "2022-01-01", image: UIImage(named: "photo1")!),
        Photo(date: "2022-01-01", image: UIImage(named: "photo2")!),
        Photo(date: "2022-01-02", image: UIImage(named: "photo3")!),
        Photo(date: "2022-01-03", image: UIImage(named: "photo4")!),
        Photo(date: "2022-01-03", image: UIImage(named: "photo5")!),
        Photo(date: "2022-01-04", image: UIImage(named: "photo6")!)
    ]
    
    var groupedPhotos: [[Photo]] = []
    
    let scrollView = UIScrollView()
    let stackView = UIStackView()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        groupPhotosByDate()
        setupScrollView()
        setupStackView()
        addPhotoViewsToStackView()
    }
    
    func groupPhotosByDate() {
        groupedPhotos = Dictionary(grouping: photos, by: { $0.date })
            .sorted { $0.key > $1.key }
            .map { $0.value }
    }
    
    func setupScrollView() {
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(scrollView)
        
        NSLayoutConstraint.activate([
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
    }
    
    func setupStackView() {
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.axis = .vertical
        stackView.spacing = 16
        scrollView.addSubview(stackView)
        
        NSLayoutConstraint.activate([
            stackView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 16),
            stackView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: -16),
            stackView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 16),
            stackView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor, constant: -16),
            stackView.widthAnchor.constraint(equalTo: scrollView.widthAnchor, constant: -32)
        ])
    }
    
    func addPhotoViewsToStackView() {
        for photos in groupedPhotos {
            let stackView = UIStackView()
            stackView.axis = .horizontal
            stackView.spacing = 8
            self.stackView.addArrangedSubview(stackView)
            
            for photo in photos {
                let imageView = UIImageView(image: photo.image)
                imageView.contentMode = .scaleAspectFit
                imageView.translatesAutoresizingMaskIntoConstraints = false
                imageView.widthAnchor.constraint(equalToConstant: 100).isActive = true
                imageView.heightAnchor.constraint(equalToConstant: 100).isActive = true
                
                stackView.addArrangedSubview(imageView)
            }
        }
    }
}

在此示例中，我们首先定义了一个Photo结构体，其中包含日期和图像。然后在ViewController类中，我们创建了一个包含一组示例照片的数组。然后，我们使用groupPhotosByDate方法将照片按日期分组。然后，我们设置了一个UIScrollView和一个垂直的UIStackView来放置照片视图。最后，我们使用addPhotoViewsToStackView方法将每个日期组的照片视图添加到垂直的UIStackView中。

这个示例可以作为一个起点，你可以根据你的实际需求进行定制和修改。