How to save the text of 2 textfields in an array?
This is what I tried. I use println to check if the values are in the array. But it seems it doesn't work.
Can anyone explain it and please, explain each step. Thank you
1- I create a swift file: novaClass.swift. I create an struct inside
struct novaClass {
var img : String
var text : String
}
2- ViewController.swift Declare an array
var nouArray = [novaClass]()
3- save the text field in the array
#IBAction func save(sender: AnyObject) {
//I put the text of 2 text fields in the array
var nouText = novaClass(img: textField1.text, text: textField2.text)
nouArray.append(nouText)
//I check the array
println(nouArray) // this gives "[_.novaClass]" I do not understand
}
That's the expected behaviour in Swift. Swift objects don't have a description property by default, so println defaults to printing the class name.
Your class can adopt the Printable protocol (which have been renamed to CustomStringConvertible in Swift 2) to provide more detailed printouts:
struct novaClass: Printable {
var img : String
var text : String
var description: String {
get {
return "{img: \(img), text: \(text)}"
}
}
}
Now try it:
var array = [novaClass]()
let x = novaClass(img: "foo", text: "bar")
let y = novaClass(img: "foo2", text: "bar2")
array.append(x)
array.append(y)
println(array) // will print: "[{img: foo, text: bar},{img: foo2, text: bar2}]"
You should check it by
println(nouArray[0].text)
println(nouArray[0].img)
Printing array as object will print its title only
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)
}
}
}
Consider the following classes
class Category {
var tag: String?
var itemList: [Item]?
}
class Item {
var id: Int?
var type: String?
var itemDetails: ItemDetails?
}
class ItemDetails {
var description: String?
var name: String?
var price: Float?
}
Given an array of Category objects.
var categoryList: [Category]
I want to create a new object array by extracting only the name in ItemDetails(inorder to apply a filter) and an id inorder to reconstruct back array of Category objects.
Hence, I have to reconstruct the array of Category objects
from new object array.
How to do both extraction and reconstruction using the map feature?
Below are the examples of other data sources:
Datasource 1 :
var categoryList: [Category], where name need to be extracted
Datasource 2 :
var searchList = [SearchItem], where title to be extracted.
Class SearchItem {
var id: Int?
var details: SearchItemDetails?
var type: String?
}
Class SearchItemDetails {
var description: String?
var title: String?
}
DataSource 3
var products: [Products], where title to be extracted.
Class Products {
var id: Int?
var details: ProductDetails?
var type: String?
}
class ProductDetails {
var description: String?
var title: String?
}
To get an array of just the names, you do the map like you mentioned:
let categories: [Category] = ... // this already exists
let itemNames = categories.map { $0.itemList?.map({ $0.itemDetails?.name }) }
But this will preserve optionals. If you don't want optionals, then use compactMap instead.
Reconstructing, however, doesn't really make any sense. Are you using the ID to hit a database or network service? That's the only possible way you'd be able to reconstruct the original array of Categorys. Why not just hold onto the original array?
I have two arrays of objects with different sizes.
First one with old data, second one with updated data from server (included old data with new), data can be mixed. I want to get difference between these arrays.
My class
class Station {
var dateOfIssue: Date
var region: String
var locality: String
var bsName: String
var freqIn: String
var freqOut: String
var networkType: String
var provider: String
var bsUsableName: String
...
}
Arrays I want to compare (example)
var a = [Station]()
var b = [Station]()
for _ in 0...5 {
a.append(Station(someRandomStationValue...)
}
b = a
for _ in 0...7{
b.append(Station(someRandomStationValue...) //array "b" will contain all that array "a" contains and some new values
}
How to compare these arrays comparing all fields between and get a new array with differences (like in java: b.removeAll(a))?
You can make use of Set which provides in-built .subtract() and .subtracting() methods which removes the common entries inside both the Sets
struct Station: Hashable,CustomStringConvertible {
var id: Int
var region: String
var locality: String
var bsName: String
// Just to provide a pretty print statement
var description: String {
return "ID: \(id) | region: \(region) | locality: \(locality) | bsName: \(bsName)"
}
}
var stations1 = Set<Station>()
var stations2 = Set<Station>()
for currentNumber in 0...3 {
stations1.insert(Station(id: currentNumber, region: "abc", locality: "abc", bsName: "abc"))
}
for currentNumber in 0...5 {
stations2.insert(Station(id: currentNumber, region: "abc", locality: "abc", bsName: "abc"))
}
// Caluculating the difference here
print(stations2.subtracting(stations1))
As pointed out by #koropok, a good solution is using Set. The first step is to conform your type to Hashable. For classes, you'd have to implement == and hash(into:) functions, but if you use struct you don't have to do anything else other than declaring the conformance. So:
struct Station: Hashable {
var dateOfIssue: Date
var region: String
...
}
Now you should be able to add Station into a Set. Thus:
var a = Set<Station>()
for _ in 0...5 {
a.insert(Station(...))
}
var b = Set<Station>()
a.forEach { b.insert($0) }
for _ in 0...7 {
b.insert(Station(...))
}
let c = b.subtracting(a)
Set also provides a handy initializer that you can use to turn your Station array into a set:
let s = Set(arrayLiteral: [your, station, objects])
As mentioned in comments by koropok you may use subtract method:
// Added to make original code functional
// Station must conform to Hashable protocol in order to be stored in the Set
struct Station: Hashable {
let id: Int
}
var a = [Station]()
for i in 0...5 {
a.append(Station(id:i))
}
var b = [Station]()
for i in 0...7{
//array "b" will contain all that array "a" contains and some new values
b.append(Station(id:i))
}
var c = Set(b)
// c will contain 6 and 7
c.subtract(a)
I wrote a model like this as an exercise :
struct Store {
var name : String
var bills : Array<Bill>
var category : Category?
}
struct Bill {
var date : String
var amount : Float
}
struct Category {
var name : String
var tags : Array<String>
}
and when I'm searching if a store already exist to add a bill to it instead of creating a new store, my code doesn't work. It acts like if the result of the search is a copy of the Array element . I would like to have a reference.
var stores : Array <Store> = Array()
for billStatment in billStatements! {
let billParts = billStatment.split(separator: ",")
if billParts.count > 0 {
let bill : Bill = Bill(date:String(billParts[0]), amount: Float(billParts[2])!)
var store : Store = Store(name:String(billParts[1]), bills: [bill], category: nil)
if var alreadyAddedStore = stores.first(where: {$0.name == String(billParts[1])}) {
alreadyAddedStore.bills.append(bill)
print("yeah found it \(alreadyAddedStore)") // the debugger breaks here so I know the "first" method is working. If I print alreadyAddedStore here I have one more element, that's fine.
} else {
stores.append(store)
}
}
}
print("\(stores.count)") // If I break here for a given store that should contains multiple elements, I will see only the first one added in the else statement.
Can anyone tell me what I am doing wrong?
As already noted, you're confusing value (struct) semantics with reference (class) semantics.
One simple fix would be the change stores to a dictionary with the name as your key:
var stores : Dictionary<String, Store> = [:]
and use it like this:
if(stores[store.name] == nil) {
stores[store.name] = store
}
else {
stores[storeName].bills.append(bill)
}
How do I sort images in order in an array type UIImage?
I'm query images from Parse, putting them in an AnyObject type array and converting it into UIImage type array.
var imagesArray:[AnyObject] = []
var uiImageArray:[UIImage] = []
To display the images I'm doing this:
func updateImageOnUI() { //Changes the UI
if imageCounter < self.imagesArray.count {
var imageElement: AnyObject = self.imagesArray[imageCounter]
var imageUpdate: AnyObject = self.imagesArray[imageCounter]
println(imageUpdate["ImageFiles"])
let userImageFile = imageUpdate["ImageFiles"] as PFFile
userImageFile.getDataInBackgroundWithBlock {
(imageData: NSData!, error: NSError!) -> Void in
if !(error != nil) {
let image = UIImage(data:imageData)
self.image.image = image
}
}
} else {
imageQuery()
}
}
Problem is, I can't sort the images so that they appear in order. They are named "image1.jpg, image2.jpg, etc"
How do I sort the images so that they repeat in order?
I've tried the sort function, but it's giving me errors
let sortedArray = sorted(imageList, {
(str1:UIImage, str2: UIImage) -> Bool in
return str1. /*not sure what to put*/ > str2./*not sure what to put*/
})
The errors I'm redesign are saying that AnyObject or UIImage aren't compatible types.
It's not possible to get the fileName of an UIImage after it is set.
You could always store the array of UIImages as [(fileName: String, image: UIImage)]. When you insert them, you add the filename (or other name you want to sort by). Then you can sort the array of tuples by fileName.