SOLVED: Unable to sort array in asc order - Hacking With Swift Project 1 challenge UIKit – Books

@somojo

Apr '20

Hey all,

Regarding the challenge at the end of Project 1 of UIKit,

Attempting to sort the array my files in ascending order but Swift fails to build, can anyone see where I'm going wrong?


//
//  ViewController.swift
//  hws_project1
//
//  Created by mojo on 15/04/2020.
//  Copyright © 2020 m. All rights reserved.
//

import UIKit

class ViewController: UITableViewController {

    var pictures = [String]()

    override func viewDidLoad() {
        super.viewDidLoad()

        title = "Storm Viewer"
        navigationController?.navigationBar.prefersLargeTitles = true

        let fm = FileManager.default
        let path = Bundle.main.resourcePath!

        let items = try! fm.contentsOfDirectory(atPath: path)

        for item in items {
            if item.hasPrefix("nssl"){
                // this is a pic to load
                pictures.append(item)
            }
        }

        //this should order the pics in ascending order but doesnt work
        picturesArray.sort(by: > )

    }
    // How many rows should appear in the table
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return pictures.count
    }
    // What each row should look like
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Picture", for: indexPath)
        cell.textLabel?.text = pictures[indexPath.row]
        return cell
    }

    // 1. try loading the vc
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if let vc = storyboard?.instantiateViewController(withIdentifier: "Detail") as? DetailViewController {
            // 2. set its selectedImage property
            vc.selectedImage = pictures[indexPath.row]

            // 3. push it on the navigation controller
            navigationController?.pushViewController(vc, animated: true)

        }
    }

    // Array of pics listed in the Content folder
    var picturesArray = ["nssl0049.jpg", "nssl0046.jpg", "nssl0091.jpg", "nssl0045.jpg", "nssl0051.jpg", "nssl0041.jpg", "nssl0042.jpg", "nssl0043.jpg", "nssl0033.jpg", "nssl0034.jpg"]

}

The code in comments where it's not working is for my own benefit so I don't lose track. it builds successfully but when you run the app in the sim, it's still displaying the files in the order I've said!

3

@somojo

Apr '20

So I tried:

        picturesArray = pictures.sorted(by: { (pic1: "nssl0049.jpg" , pic2: "nssl0046.jpg" ) -> Bool in
            return pic1 > pic2
        })

But this fails to build, I'm trying to run a few sims in Playground but no success

3

@somojo

Apr '20

With infered type, this works when I print it out:

picturesArray.sort()

But that's it so far, unsure how to alter the contents of FileManager so it's displayed how I wish to

3

@delawaremathguy

Apr '20

hi,

i'm not sure what your picturesArray is doing, because you define it; you attempt to sort it (the closure you attempted give for the sort is suspicious); but you never use it. the UITableView is driven by the pictures array and does not depend on picturesArray.

just add a .sorted() function call on the items in the for loop that appends the filenames to the pictures array (then, deep-six what you call picturesArray):

        let fm = FileManager.default
        let path = Bundle.main.resourcePath!
        let items = try! fm.contentsOfDirectory(atPath: path)
        for item in items.sorted() {
            if item.hasPrefix("nssl") {
                pictures.append(item)
            }
        }

alternatively, just sort the pictures array after it is flled with filenames:

        let fm = FileManager.default
        let path = Bundle.main.resourcePath!
        let items = try! fm.contentsOfDirectory(atPath: path)
        for item in items {
            if item.hasPrefix("nssl") {
                pictures.append(item)
            }
        }
        pictures.sort()

that should do it.

hope that helps, DMG

5

@somojo

Apr '20

Hey @delawaremathguy I've just added that line into the pictures load IF statement before I saw this and bloody hell it works, can't believe it's that simple! I feel like a fool!

3

@delawaremathguy

Apr '20

hi,

please do not worry about feeling foolish -- not only do i do something pretty silly every day, but i fully expect that i'll do something silly every day. the trick is to think it out a little and learn from it. that's what makes each of us better at this stuff.

good luck going forward, DMG

--

6

	@somojo Apr '20 Hey all, Regarding the challenge at the end of Project 1 of UIKit, Attempting to sort the array my files in ascending order but Swift fails to build, can anyone see where I'm going wrong? // // ViewController.swift // hws_project1 // // Created by mojo on 15/04/2020. // Copyright © 2020 m. All rights reserved. // import UIKit class ViewController: UITableViewController { var pictures = [String]() override func viewDidLoad() { super.viewDidLoad() title = "Storm Viewer" navigationController?.navigationBar.prefersLargeTitles = true let fm = FileManager.default let path = Bundle.main.resourcePath! let items = try! fm.contentsOfDirectory(atPath: path) for item in items { if item.hasPrefix("nssl"){ // this is a pic to load pictures.append(item) } } //this should order the pics in ascending order but doesnt work picturesArray.sort(by: > ) } // How many rows should appear in the table override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return pictures.count } // What each row should look like override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCell(withIdentifier: "Picture", for: indexPath) cell.textLabel?.text = pictures[indexPath.row] return cell } // 1. try loading the vc override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { if let vc = storyboard?.instantiateViewController(withIdentifier: "Detail") as? DetailViewController { // 2. set its selectedImage property vc.selectedImage = pictures[indexPath.row] // 3. push it on the navigation controller navigationController?.pushViewController(vc, animated: true) } } // Array of pics listed in the Content folder var picturesArray = ["nssl0049.jpg", "nssl0046.jpg", "nssl0091.jpg", "nssl0045.jpg", "nssl0051.jpg", "nssl0041.jpg", "nssl0042.jpg", "nssl0043.jpg", "nssl0033.jpg", "nssl0034.jpg"] } The code in comments where it's not working is for my own benefit so I don't lose track. it builds successfully but when you run the app in the sim, it's still displaying the files in the order I've said! 3
	@somojo Apr '20 So I tried: `picturesArray = pictures.sorted(by: { (pic1: "nssl0049.jpg" , pic2: "nssl0046.jpg" ) -> Bool in return pic1 > pic2 })` But this fails to build, I'm trying to run a few sims in Playground but no success 3
	@somojo Apr '20 With infered type, this works when I print it out: `picturesArray.sort()` But that's it so far, unsure how to alter the contents of FileManager so it's displayed how I wish to 3
	@delawaremathguy Apr '20 hi, i'm not sure what your picturesArray is doing, because you define it; you attempt to sort it (the closure you attempted give for the sort is suspicious); but you never use it. the UITableView is driven by the pictures array and does not depend on picturesArray. just add a .sorted() function call on the items in the for loop that appends the filenames to the pictures array (then, deep-six what you call picturesArray): `let fm = FileManager.default let path = Bundle.main.resourcePath! let items = try! fm.contentsOfDirectory(atPath: path) for item in items.sorted() { if item.hasPrefix("nssl") { pictures.append(item) } }` alternatively, just sort the pictures array after it is flled with filenames: `let fm = FileManager.default let path = Bundle.main.resourcePath! let items = try! fm.contentsOfDirectory(atPath: path) for item in items { if item.hasPrefix("nssl") { pictures.append(item) } } pictures.sort()` that should do it. hope that helps, DMG 5
	@somojo Apr '20 Hey @delawaremathguy I've just added that line into the pictures load IF statement before I saw this and bloody hell it works, can't believe it's that simple! I feel like a fool! 3
	@delawaremathguy Apr '20 hi, please do not worry about feeling foolish -- not only do i do something pretty silly every day, but i fully expect that i'll do something silly every day. the trick is to think it out a little and learn from it. that's what makes each of us better at this stuff. good luck going forward, DMG -- 6

SOLVED: Unable to sort array in asc order - Hacking With Swift Project 1 challenge UIKit

Archived topic