I don't know how to find array value of that particular index which user has typed. I had connected that array to my data model which contain 2 values ?
I have tried .contain value after implementing a new variable of the data model but it hasn't worked
let productsNamess = document.data()["ProductName"] as! String
let quantityGame = document.data()["Quantity"] as! String
// making a new net stock data incoming class
let newClassForProducts = dataModelOutgoing()
newClassForProducts.productName = productsNamess
newClassForProducts.quantity = Int(quantityGame)
// forward data to main dataincoming main class
self.dataIncoming.append(newClassForProducts)
I dont know how to take data out of an array which contains two values in one array.
Related
I'm just starting up with RealmSwift, and I'm trying to store an array of Strings in Realm. It doesn't work, so now I'm using List<String>() as an alternative. However, how do I convert these Realm Lists back to [String] again? And if I can't do that, are there any alternatives?
Thanks
However, how do I convert these Realm Lists back to [String] again
You can simply cast List to Array, because List has Sequence Support:
let list = List<String>()
let array = Array(list)
Bear in mind that by converting to an array you'll lose the 'dynamic' quality of a Realm collection (i.e. you'll receive a static array, whereas keeping the original List will provide automatic updating should the source change). But you can create an array by using an extension, e.g.:-
extension RealmCollection
{
func toArray<T>() ->[T]
{
return self.compactMap{$0 as? T}
}
}
Then use:-
let stringList = object.strings.toArray()
Where object is the realm object, and strings is your field.
Here are the details. how to assign an array in the realm list model.
jim.dogs.append(objectsIn: someDogs)
I want to convert the results from my Realm data into Int.
Here is an example of how I want to use this.
let results = realm.objects(Data.self)
print(results)
However the result is type Results<Data> and cannot be converted into a Int but the results is an Int.
Just to be clear I want an array of Int from my results
You can simply use Array(realm.objects(RealmType.self)), which will convert the Results<RealmType> instance into an Array<RealmType>.
However, there are other serious flaws with your code. First of all, neither of the last two lines will compile, since firstly realm.objects() accepts a generic input argument of type Object.Type and Data doesn't inherit from Object. You can't directly store Data objects in Realm, you can only store Data as a property of a Realm Object subclass.
Secondly, myArray[results] is simply wrong, since results is supposed to be of type Results<RealmType>, which is a collection, so using it to index an Array cannot work (especially whose Element type is different).
It appears that based on the number of results from the database, you want to select an object from the array.
You can get the number of items in an array with .count. Be certain that an object exists at the specified index in the array, or your application will crash!
let numberOfResults = results.count
if myArray.count > numberOfResults {
let object = myArray[numberOfResults]
print(object)
}
I am trying to implement a dictionary data structure in swift that stores an Array of Strings. I have declared it like:
var journeyDetails = [Int: [String]]()
When I want to append an actual string to it, I do
if let journeys = fetchedData["journeys"] as? [[String: Any]]{
var nr_of_journey : Int = 0
for journey in journeys{
self.journeyDetails[nr_of_journey]?.append("The starting date and time of the journey are: "+String(describing: journey["startDateTime"]))
}
}
nr_of_journey = nr_of_journey + 1
etc etc. However, journeyDetails keeps returning nil. Should I do any other type of initialization? Why is the data not appended?
Initially there are no keys or values in journeyDetails so every use of self.journeyDetails[nr_of_journey] returns nil.
If you are using Swift 4, you can specify a default value to be used if there currently isn't a value for the given key.
Update the line:
self.journeyDetails[nr_of_journey]?.append("The starting date and time of the journey are: "+String(describing: journey["startDateTime"]))
to:
self.journeyDetails[nr_of_journey, default: []].append("The starting date and time of the journey are: "+String(describing: journey["startDateTime"]))
This provides a default empty array if there currently isn't a value for the given nr_of_journey key.
I have an array of classes, which looks like this:
var myItems = [myClass]()
class myClass: NSObject {
var a: String?
var b: String?
var c: String?
var d: String?
}
What I want is to save the array called myItems into my database, and have every class inside of a personal section inside the database. Basically, I want every class to look like the one called "Eko" in this image:
To clarify, after "Eko" all the rest of the classes which is inside of the array myItems should be displayed. To achieve what the picture is demonstrating, I used this code:
let data = self.myItems[0]
let currU = FIRAuth.auth()?.currentUser?.uid
let userRef = self.ref.child("users").child(currU!).child(data.a!)
userRef.updateChildValues(["a": data.a!, "b": data.b!, "c": data.c!, "d": data.d!])
Obviously, this will only save the class at index 0 from the array myItems into the Firebase Database, which is displayed in the image above.
My question is thus, how do I save the entire array into the database? With my code I can only save 1 class from the array, and I would like to save all of the items into the database, so that they end up looking the same way that the one class does in the image. You could compare this to populating a tableView, where you need the "indexPath.row" to populate it with all the items instead of only one. I hope that I was clear enough!
You can't save a class into Firebase. But.. A class has a similar structure to a dictionary (properties and values, like key: value pairs etc).
Arrays in Firebase should generally be avoided - they have limited functionality and the individual elements cannot be accessed and for any changes you have to re-write the entire array.
Using a structure where the parent key names are created with childByAutoId is usually preferred.
The easiest solution is to simply add intelligence to the class so it would craft a dictionary and then save itself.
Craft a user class
UserClass
var name = String()
var food = String()
func saveToFirebase() {
let usersRef = myFirebase.child(users)
let dict = ["name": self.myName, "food", self.myFood]
let thisUserRef = usersRef.childByAutoId()
thisUserRef.setValue(dict)
}
}
and and array to store them
var usersArray = [Users]()
populate the array
var aUser = UserClass()
aUser.name = "Leroy"
aUser.food = "Pizza"
usersArray.append(aUser)
var bUser = UserClass()
bUser.name = "Billy"
bUser.food = "Tacos"
usersArray.append(bUser)
and then iterate over the array saving each user
for user in usersArray {
user.saveToFirebase()
}
this will result in
users
-Ykasokokkpoad
name: Leroy
food: Pizza
-YJlaok9sk0sd
name: Billy
food: Tacos
which is very similar to the structure you want. There are many other ways of creating this structure. For example, you could craft the entire dictionary in code and write it all out at one time.
Pardon typo's, I wrote this on the fly.
Firebase has no native support for arrays. If you store an array, it really gets stored as an "object" with integers as the key names.
// we send this
['hello', 'world']
// Firebase stores this
{0: 'hello', 1: 'world'}
Read this post for better understanding.
After already having parsed my data through swiftyjson I am looking to display the parsed information in a uitableview. Let's say I have a list of names that I parsed out of the json file. I would like those names to display each in their own respective cells to allow the user to view them all.
I would also assume that if they selected the selected cells which are being displayed strings now after being parsed that I can actually have those stored into a core data object storing them as returnable strings? The thing is I used the .append function onto an array that I created we'll call names = [String]() to actually allow the values to actually come in order for the cells.
But when doing this I noticed a huge spike in cpu usage doing this as it keeps appending them in order lets say first name is matt second name is john and so forth then it creates a new situation of the array every time. so the first time it reads just matt then the next println would print out matt, john then the next one prints out matt, john, tom and so forth until the list of json names is completed.
If I have 500 names or more it takes the cpu awhile to process all those names into the array. I know there has to be another way but all references I see all use the .append method. So my code would be names.append(Name). Name is a parsed string from swiftyjson. From there I am actually able to populate the tableview which is fine it displays correctly in the end but it takes the device awhile to populate as it first needs to process adding all 500 names each time the parse is called. I am hoping to allow the 500 names be rechecked every time in case new ones have been added. This all stores currently as a local json file already.
The code I am using is below I can figure out the UItableview part but it's more a question of whether appending an array is the best and most efficient way of displaying the parsed data from swiftyjson.
let path = NSBundle.mainBundle().pathForResource("List", ofType: "json")
let jsonData = NSData(contentsOfFile: path!, options: NSDataReadingOptions.DataReadingMappedIfSafe, error: nil)
let json = JSON(data: jsonData!)
for (key, subJson) in json["array"] {
if let Name = subJson["Name"].string {
NameList.append(Name)
println(NameList)
}
}
maybe the Swift map function is more effective
…
let json = JSON(data: jsonData!)
var nameList = [String]()
if let subJson = json["array"] as [Dictionary<String,NSObject>]? {
nameList = subJson.map { $0["name"] as! String }
}