I have 2 Types, first is Car with property feature and it of the second type Feature.
I have a property cars: [Car], when I append new car to it, it returns nil.
I have created a sample in the snippet below:
class Car {
let make: String
var features: Feature?
let id: String
init(make: String, features: Feature?, id: String) {
self.make = make
self.features = features
self.id = id
}
}
class Feature {
let convertible: String
init(convertible: String) {
self.convertible = convertible
}
}
var cars: [Car]?
var feature: Feature?
let featureElement = Feature(convertible: "yes")
feature = featureElement
let car = Car(make: "SomeMaked", features: feature, id: "ID")
cars?.append(car)
print(cars)
My question is: Shouldn't the array increase its count after appening to it? What am I missing?
Please note that this code is just sample, so ignore typos and coding convention.
You haven't initialized your array.
Replace your var cars: [Car]? with var cars: [Car]? = []
Related
Tried to combine or merging two model to one model
1st model = items [ InboxModel]. (My own Inbox)
2nd model = items2 [MoInboxModel] (SDK Inbox)
1st + 2nd -> combinedItems
private var items: [InboxModel] = []
private var items2: [MoInboxModel] = []
private var combinedItems: [combinedInboxModel] = []
struct InboxModel {
let id: String
let title: String
let message: String
let date: Date
}
struct MoInboxModel {
let id: String
let title: String
let message: String
let date: Date
}
struct combinedInboxModel {
let id: String
let title: String
let message: String
let date: Date
}
self?.combinedItems.append(self?.items). //No exact matches in call to instance method 'append
self?.combinedItems.append(contentsOf: self?.items2 ?? []) //No exact matches in call to instance method 'append
Why there is an error while merge it ? How to merge it correctly?
You have three unrelated types - InboxModel, MoInboxModel and combinedInboxModel (Which should be CombinedInboxModel. Even though they all have properties with the same name, they are different types.
There is no append function on an array of combinedInboxModel that accepts an array of InboxModel or MoInboxModel.
You could use map on each of your two input arrays to convert them to an array of CombinedInboxModel which you can then put into combinedItems.
Presumably you are writing this code in a closure, which is why you have a weak self. Best to deal with that first and then process your arrays.
guard let self = self else {
return
}
self.combinedItems = self.items.map { CombinedInboxModel(id:$0.id,title:$0.title,message:$0.message,date:$0.date) }
let items2 = self.items2.map { CombinedInboxModel(id:$0.id,title:$0.title,message:$0.message,date:$0.date) }
self.combinedItems.append(contentsOf:items2)
You haven't shown where items and items2 come from; Is it possible just to fetch them as instances of the same struct to start with?
The fact that you have three structs with the same properties is a bit fishy. I would consider a different design if I were you.
However, if you must go with this approach, you might want to consider starting with a protocol and getting rid of the combinedInboxModel struct.
protocol InboxModelable {
var id: String { get }
var title: String { get }
var message: String { get }
var date: Date { get }
}
Now make your two structs conform to InboxModelable.
struct InboxModel: InboxModelable {
let id: String
let title: String
let message: String
let date: Date
}
struct MoInboxModel: InboxModelable {
let id: String
let title: String
let message: String
let date: Date
}
Since both of your types conform to InboxModelable you can directly store both types in an array of type Array<InboxModelable> without having to map the elements.
class SomeClass {
private var items: [InboxModel] = []
private var items2: [MoInboxModel] = []
private var combinedItems: [InboxModelable] = []
func combineItems() {
doSomething { [weak self] in
guard let self = self else { return }
self.combinedItems.append(contentsOf: self.items)
self.combinedItems.append(contentsOf: self.items2)
}
}
}
I'm tryin' to obtain a list of activities ("dd/mm/YY: goal achieved/missed goal") which has to be setted every week. The problem is that I obtain a list of activities with the same date and the same result of the previous one. For example:
28/02/2022: goal achieved
28/02/2022: goal achieved
28/02/2022: goal achieved
and the next day:
01/03/2022: missed goal
01/03/2022: missed goal
01/03/2022: missed goal
01/03/2022: missed goal
I want to obtain, instead, a list like:
28/02/2022: goal achieved
01/03/2022: missed goal
02/03/2022: goal achieved...
These are useful structs:
struct Persistent {
#AppStorage("goalAchieved") static var goalAchieved : Bool = false
#AppStorage("activityList") static var activityList : [String] = []
}
struct obj {
static var currentDate = Date()
static var stringDate = ""
static var activity = Activity(date:Persistent.lastUpdatedDate)
}
This is the ActivityListView:
import SwiftUI
func activitystring(activity:Activity) -> String{
var output = ""
output = "\(activity.date): \(activity.reachedobj(goalAchieved: Persistent.goalAchieved))"
return output
}
struct Activity: Identifiable{
let id = UUID()
let date: String
func reachedobj(goalAchieved: Bool) -> String {
var output = ""
if Persistent.goalAchieved == false { output = "Missed goal" }
if Persistent.goalAchieved == true { output = "Goal Achieved!"}
return output
}
}
struct ActivityRow: View{
var activity: Activity
var body: some View{
Text(activitystring(activity: activity))
Divider()
}
}
struct ActivityListView: View {
var body: some View {
ScrollView{
Text("Week summary").font(.system(size: 15)).foregroundColor(Color.green)
Text("")
ForEach(Persistent.activityList, id: \.self) { activity in
let activity = Activity(date: Persistent.lastUpdatedDate)
ActivityRow(activity: activity)
}
}
}
}
Finally this is the useful code in the ApplicationApp file (main) where I update activity list:
MenuView().onAppear(){
if Persistent.activityList.count>7{
Persistent.activityList.removeAll()
}
obj.currentDate = Date()
let formatter = DateFormatter()
formatter.dateFormat = "dd/MM/YY"
obj.stringDate = formatter.string(from:obj.currentDate)
if Persistent.lastUpdatedDate != obj.stringDate{
Persistent.goalAchieved = false
let activity = Activity(date: Persistent.lastUpdatedDate)
Persistent.activityList.append(activitystring(activity: activity))
Persistent.lastUpdatedDate = obj.stringDate
}
}
What's wrong on this?
You're calling obj.activity in your ForEach and ActivityRow, that's why it repeats that same static property all over the place.
You better just drop your struct obj and try again without it
In your Persistent object you have an array of many activities, called activitylist , but one single boolean that tells if the goal is achieved - goalachieved indeed.
Your view is iterating through the array of Persistent.activitylist, so you will have many lines for one single result - achieved or not achieved. You might actually want to iterate over an array of Persistent objects - meaning that somewhere you should probably store [Persistent] in some variable. In this way, you will see one line only for each result.
If I also may suggest: use the conventions for naming variables, Swift uses "camelCaseConventionForVariables", easier to read than "thewholevariableislowercase"
Edit:
Let me try to change a little bit your code (I would personally change it more radically, but that's not the scope of the answer).
Instead of having only one goalAchieved for all elements on the array activityList, make it a dictionary:
struct Persistent {
// Drop this variable
// #AppStorage("goalAchieved") static var goalAchieved : Bool = false
// Make this a dictionary, the date will be the key and the goalAchieved will be the value
#AppStorage("activityList") static var activityList : [String: Bool] = [:]
}
Add values to the dictionary (#meomeomeo is right, you don't need obj):
MenuView().onAppear() {
if Persistent.activityList.count > 7 {
Persistent.activityList.removeAll()
}
let currentDate = Date()
let formatter = DateFormatter()
formatter.dateFormat = "dd/MM/YY"
let stringDate = formatter.string(from: currentDate)
if Persistent.lastUpdatedDate != stringDate {
let activity = Activity(date: Persistent.lastUpdatedDate)
Persistent.activityList[activitystring(activity: activity))] = false // Will create something like ["01/03/2022": false]
Persistent.lastUpdatedDate = stringDate
}
}
Iterate on the dictionary in your ForEach; for more info: read here.
I’m building search functionality. I have an array of User objects and each User has a dictionary of tags. I’m trying to return users with searched tags.
My user class is:
class User: NSObject {
var name: String?
var tags = Dictionary<String, String>()
}
An example of the tags is:
tags: {
“entry1” : “test1”,
“entry2” : “test2”,
“entry3” : “test3”
}
I’ve been trying variances of:
let predicate = NSPredicate(format: “tags contains[c] %#", “test1”);
let filteredArray = self.usersArray!.filter { predicate.evaluate(with: $0) }; print(“users = ,\(filteredArray)");
It’s throwing “this class is not key value coding-compliant for the key tags.’ I'm not sure how to search inside the User object.
Update:
I've change the dictionary to an array and
filter { $0.tags.contains(searchTerm) } works for exact search match, as suggested.
.filter( {$0.tags.reduce(false, {$1.contains(searchTerm)} )} ) does not work for a partial match however, which is what i'm looking for.
Here is what is printed:
Search term: ale
Result: []
Tags array inside each object:
["Alex", "Will", ""]
["Bob", "Dan", ""]
["First", "Second", "Third"]
["Testing 1", "Testing 2", ""]
Your implementation of tags seems cumbersome. Here is a simpler one.
class User {
var name: String
var tags: [String]
}
Now let's say you have an array of users in users.
var users: [User]
// Store users in the array
Now, this is how you check which user contains a particular tag.
let tag = "yourTag"
users.filter( { $0.tags.contains(tag) } )
However, if you are adamant that you need the tags in a dictionary, then you could do it like this,
users.filter( {$0.tags.values.contains(tag)} )
If you want to check if the tag is part of any of the tags in a particular user, you could do it like this,
let filteredUsers = users.filter( {$0.tags.reduce(false, {$1.contains(tag)} )} )
P.S - we don't use ; in Swift.
It's good practice to make your models conform to Codeable:
struct User: Codable {
var userId: UUID
var name: String = ""
var referenceTags: [String: String] = [:]
}
// Create some users:
let Bob = User(userId: UUID(), name: "Bob", referenceTags: ["tag1": "no", "tag2": "yes"])
let Steve = User(userId: UUID(), name: "Steve", referenceTags: ["tag2": "no", "tag3": "no"])
Create an array of users to filter.
let users:[User] = [Bob, Steve]
Get a search predicate or string from your Search bar or other.
let searchPredicate = "yes"
Filter and iterate over tags for the required value.
let results = users.filter { (user) -> Bool in
for (key, _) in user.referenceTags.enumerated() {
if (user.referenceTags[key] == searchPredicate) {
return true
}
}
}
I'm new to Realm and have been through the documentation a few times. I need to persist a [[String]] and have not found a way to do it yet
var tableViewArray = [[String]]()
I see the documentation pointing to Lists but I've been unsuccessful at implementing them. I'm showing my whole process here but just need help persisting my var tableViewArray = [[String]]()in Realm
This is my class
class TableViewArrays {
var tableViewArray = [[String]]() // populates the Main Tableview
/// add picker selection to tableview array
func appendTableViewArray(title: String, detail: String, icon: String ) {
var newRow = [String]()
newRow.append(title)
newRow.append(detail)
newRow.append(icon)
tableViewArray.append(newRow)
}
In the View Controller I instantiate the object
var tableViewArrays = TableViewArrays()
Then call the class function to populate the object
var tableViewArrays.appendTableViewArray(title: String, detail: String, icon: String )
Thank you for taking a look
I would make two Realm objects to be persisted, then nest them. Here's an example:
class RealmString: Object {
dynamic var value = ""
}
class RealmStringArray: Object {
let strings = List<RealmString>()
}
class TableViewArray{
let stringArrays = List<RealmStringArray>()
}
I can't say much about the efficiency of this method, but I suppose it should work for your purpose. Also, if you have a large amount of data, it may become a pain to persist each individual string, then string collection, the string collection collection.
create the classes
class TableViewRow: Object {
dynamic var icon = ""
dynamic var title = ""
dynamic var detail = ""
override var description: String {
return "TableViewRow {\(icon), \(title), \(detail)}" }
}
class EventTableView: Object {
let rows = List<TableViewRow>()
}
then instantiate the objects and append
let defaultTableview = EventTableView()
let rowOne = TableViewRow()
rowOne.icon = "man icon" ; rowOne.title = "War Hans D.O.P." ; rowOne.detail = "Camera Order Nike 2/11/17"
defaultTableview.rows.append(objectsIn: [rowOne])
I have the below class and I use a function math to search the string in both SongTitle and in ESongTitle.
class KeerthanaiArray: NSObject {
var SongTitle: String = String()
var SongLyrics: String = String()
var ESongTitle: String = String()
init(SongTitle: String, SongLyrics:String, ESongTitle: String) {
self.SongTitle = SongTitle
self.SongLyrics = SongLyrics
self.ESongTitle = ESongTitle
}
class func match(string:String) -> Bool {
return SongTitle.containsString(string) || ESongTitle.containsString(string)
}
}
I get the error message 'Instance member SongTitle cannot be used on type 'Keerthanaiarray'. Please help
I need to declare the math func as class as I need to use the math function outside of its class
There are several problems here.
This class KeerthanaiArray is not an array (as suggested by the name instead)
Why are you extending NSObject?
The class method match makes no sense, it is using 2 properties (SongTitle and ESongTitle) that does not exists in this context because they belongs to an instance of the class.
So let's cleanup your code
struct Song {
let title: String
let lyrics: String
let eTitle: String
func match(keyword: String) -> Bool {
return title.containsString(keyword) || eTitle.containsString(keyword)
}
}
I make you class a struct because makes more sense. You are free to turn back to class. If you stay on structs please keep in mind they are value types.
Now given a list of Song(s)
let songs: [Song] = ...
and a keyword
let keyword = "The Great Gig In the Sky"
this is how we search the array
let results = songs.filter { $0.match(keyword) }
Case insensitive version
struct Song {
let title: String
let lyrics: String
let eTitle: String
func match(keyword: String) -> Bool {
let lowerCaseKeyword = keyword.lowercaseString
return title.lowercaseString.containsString(lowerCaseKeyword) || eTitle.lowercaseString.containsString(lowerCaseKeyword)
}
}