I have this Object Array mention below . Can someone please guide me how can i access various values inside the Object Array.
CellInfo(date: "Sep 2018",
audioFileInfos: [In.PtV.AudioFileInfo(urlString: "https://GeorgeB.m4a",
text: "9/11")
])
i want to Access Date ,urlString and text
struct AudioFileInfo {
let urlString: String
let text: String
init(dict: [String: String]) {
urlString = dict["AudioFileURL"] ?? ""
text = dict["Title"] ?? ""
}
}
struct CellInfo {
let date: String
let audioFileInfos: [AudioFileInfo]
}
Consider the following code.
let cellInfo = CellInfo(date: "Sep 2018",
audioFileInfos: [In.PtV.AudioFileInfo(urlString: "https://GeorgeB.m4a",
text: "9/11")
])
print(cellInfo.date) // prints date
print(cellInfo.audioFileInfos[0].urlString) // prints urlString
print(cellInfo.audioFileInfos[0].text) // prints urlString
The things is happening here is as follows
You create CellInfo struct with date and audioFileInfos.
while providing audioFileInfos you create another struct using the same way as #1
You pass the AudioFileInfo inside of array.
So incase of accessing the date you can directly access the date property using dot . operator.
For accessing the AudioFileInfo struct object, same way just with indexing added.
As audioFileInfos is an array, safe & complete way to access it's values is to traverse the array, meanwhile accessing the array elements.
for audioFileInfo in cellInfo.audioFileInfos {
print(audioFileInfo.urlString)
print(audioFileInfo.text)
}
Related
I need my app to display a table of data. The data looks like ["body": Optional("Go Shopping"), "isDeleted": Optional(false), "_id": Optional("63333b1600ce507b0097e3b3"), "isCompleted": Optional(false)] The column headers for the table would be the keys body, isDeleted, isCompleted, _id. I will have multiple instances of this data that will have the same keys, but different values. I will need to display the values for each data instance under the respective header and each row will belong to one data instance.
Example:
I'm struggling because the only way I can think of doing this is with a dictionary, but run into a lot of problems when using a dictionary in the View.
*** Important Note:
The app allows a user to select a certain collection and then the app will load all the data for that collection. Each collection has different keys in its data, so I cannot create a specific struct since I won't actually know the keys/values in the data. The model will have to be dynamic in the sense that I don't know what key/value types will be used in each collection and the table will need to redraw when a different collection is selected.
What I Tried
A document class that would hold a 'value: [String: Any?]` the string would be the key and the Any is the value from the data instance
class Document{
let value: [String:Any?]
init(value:[String:Any?]) {
self.value = value
}
}
in my ViewModel I have a call to a database that uses the selected collection name to return an array of all the documents from that collection. I loop through the array and create a Document obj with the value of the Document looking like ["body": Optional("Go Shopping"), "isDeleted": Optional(false), "_id": Optional("63333b1600ce507b0097e3b3"), "isCompleted": Optional(false)] and I add each Document to an array of Document's
class DocumentsViewModel : ObservableObject {
#Published var docKeys: [String]?
#Published var docsList: [Document]?
func getDocs() {
... //Database call to get docs from collection
for doc in docs {
// add doc keys to array (used for table header)
self.docKeys = doc.value.keys.map{$0}
self.docsList?.append(Document(value: doc.value))
}
Then in my View I tried to first display a header from the docKeys and then use that key to loop through the array of [Document] and access the value var and use the key to get the correct value to display under the header for that document
var body: some View {
Text(viewModel.collectionName)
HStack {
ForEach(viewModel.docKeys ?? [], id: \.description) {key in
Text(key.name)
VStack {
ForEach(viewModel.docsList ?? [], id: \.value) { doc in
Text(doc.value[property.name])
}
}
}
}
}
After doing research I understand why I can't ForEach over an unsorted dictionary.
I will accept any help/guidance on how I can display this table. Also, if there is any other suggestions besides using a dictionary? THANK YOU!
**Update
I was able to get it working with an ordered collection
class Document : Hashable, Equatable{
static func == (lhs: Document, rhs: Document) -> Bool {
lhs.id.description == rhs.id.description
}
let id: String
let value: OrderedDictionary<String,Any?>
init(id: String, value: OrderedDictionary<String,Any?>) {
self.id = id
self.value = value
}
func hash(into hasher: inout Hasher) {
hasher.combine(id)
}
}
Since it is ordered this allowed me to iterate of the dictionary in the View
Just a a few hints:
If you need "dictionary with order" you can try to use a Key-ValuePairs object which is essentially an array of tuples with labels key and value
let values: KeyValuePairs = ["key1": "value1", "key2": "value2"]
when you print this to the console you'll realize that this is just a tuple!
print(values[0]) will display (key: "key1", value: "value1")
please take a look at OrderedDictionary from The Swift Collections https://www.kodeco.com/24803770-getting-started-with-the-swift-collections-package
have you consider to use an array of simple structs instead?
struct Document {
let body: String?
let isDeleted: Bool?
let id: String?
let isCompleted: Bool?
...
}
I m mapping data that come from service with using dictionary [String: String]. I collect them dictionary array. For example, if their parent ids are the same, I want to add their values by array value.
["ParentId": "1","Value": "["Giyim","Aksesuar","Ayakkabı"]"]
It is also the reason I don't know parent id sometimes on the left sometimes on the right in photo
Here is my code and its output.
struct Categories {
let parentId: String
let values: [String]
}
for result in results {
if result?.parentCategoryId != "" {
for docId in self.docIds {
if result?.parentCategoryId == docId {
//print(result?.name)
var values = [String]()
values.append(result?.name ?? "")
self.newCat.append(Categories(parentId: docId, values: values))
}
}
}
}
Problem
As far as I understand from the description you want to map some service data structure to a dictionary where key is parentId and value is an array of some items referred to parentId.
I believe your problem comes from a misunderstanding of the concept of dictionary as a data structure.
[String: String] is dictionary where keys and their associated values are of String type. For example:
["firstKey": "firsthValue", "secondKey": "secondValue", ...]
That means you cannot store associated values of String and Array types in the same dictionary, as you already told the compiler you would like to store only strings.
It is also the reason I don't know parent id sometimes on the left sometimes on the right in photo
This is because key-value pairs are stored in the dictionary without order. This is how dictionaries work :) I'd strongly recommend reading some short official materials to get used to them.
New Swift 5.4 version has a new OrderedDictionary data structure, where keys are ordered, but there is absolutely 100500% no reason to use it for your problem*
Possible solutions
In your case i would suggest either use some struct:
struct SomeData {
let parentID: Int
var values: [String]
}
var storage: [SomeData] // alternative to emptyDic
// Filling storage with data from service
for result in inputData {
// search for SomeData with required id, add value
// OR create SomeData if there is no such id in array yet
}
OR [personally this appeals to me more]
Store data in [String: [String]] dictionary, where the key is parentID and the associated value is an array of values.
The algorithm of filling this dictionary is pretty the same:
You add new key-value pair for every new parentID
You append new values for parentIDs that are already in the dictionary.
Using the struct approach, you could do something like this (you'll need to adapt it to your code, but that should be straightforward):
struct Categories {
let parentId: String
var values: [String] //notice this needs to be a var, not a let
}
func addItem(categories : inout [Categories], docId: String, name: String) {
if let index = categories.firstIndex(where: { $0.parentId == docId }) {
categories[index].values.append(name)
} else {
categories.append(Categories(parentId: docId, values: [name]))
}
}
func addValues() {
var categories = [Categories]()
addItem(categories: &categories, docId: "4", name: "Test1")
addItem(categories: &categories, docId: "1", name: "Test")
addItem(categories: &categories, docId: "4", name: "Test2")
addItem(categories: &categories, docId: "4", name: "Test3")
print(categories)
//in your code, it'll look more like:
// addItem(categories: &self.newCat, docId: docId, name: result?.name ?? "")
}
Which yields this:
[
StackOverflowPlayground.Categories(parentId: "4", values: ["Test1", "Test2", "Test3"]),
StackOverflowPlayground.Categories(parentId: "1", values: ["Test"])
]
I still wonder whether you maybe just want a Dictionary that is keyed by the parentId, but not knowing your use case, it's hard to say.
I want to parse the json string and displays in the UITextView.
I am getting the data with HTML string with key and values. This is the below sample string response from the server,
{"":"<strong>Adidas<\/strong><br>Enjoy 10% off","Period":"10 Oct 2019 - 11 Nov 2019","Description":"<p>Enjoy 30% off
"Terms & Conditons":"<ol>\n<li>It's available only in peak hours<\/li>\n}
I need to display like the below format with HTML,
Expected output:
Adidas
Enjoy 10% off
Period:
10 Oct 2019 - 11 Nov 2019
Description:
Enjoy 30% off.
Terms & Conditons:
It's available only in peak hours
I've used dictionary and extracted the data but the problem is order of the data is not in sequence.
func setupData(responseString : String)
{
// Convert string to dictionary for extracting the keys and values
// Need to maintain the order while adding the data
let content = convertToDictionary(text: responseString)
var text : String = ""
if let contentDataDict = content
{
for (key, value) in contentDataDict
{
// want to append the key and values in the sequence order
textView.attributedText = text.htmlToAttributedString
}
}
}
How can I parse and display the data as per the expected output.
Devan, you're right in your thinking that a dictionary won't work. You'd be better loading the html into an array. I've used pseudocode as to represent a new convertToArray to replace your convertToDictionary as you didn't supply all the original code
struct Component {
field: String
value: String
}
func convertToArray(response: String) -> [Component] [
let components = [Component]()
for entries in response {
//extract key/value pairs from html as before
//then create a component struct with them and add it to the array
components.append(Component(field: key, value: value)
}
return components //now a sequence of structs represent your data in order
}
func setupData(responseString : String) {
let components: [Component] = convertToArray(text: responseString)
for component in components {
//add component.field and component.value to your attributed text string
//and then display as before
}
}
How can I decode the following using swift Decodable? I'm only interested in the extract value
{
"batchcomplete":"",
"query":{
"normalized":[ ],
"pages":{
"434325":{ //can be any number!
"pageid":434325,
"ns":0,
"title":"asdfasdfsa",
"extract":""
I'm attempting the following:
struct Entry: Decodable {
let batchcomplete: String
let query: Query
struct Query: Decodable {
let normalized: [String]
let pages: Page
struct Page: Decodable {
let pageid: Entry // I think this is going to be an issue
struct Entry: Decodable {
let title: String
let extract: String
}
}
}
}
I'm trying to retrieve the extract like this:
print(entry.query.pages.first.extract)
Is there a way to use .first for this ?
I'm only every going to get maximum one page so ideally I would just grab the first element.
Your decoding code is ok up until `Query type.
So what should be used instead:
struct Query: Decodable {
let normalized: [String]
let pages: [String: Page]
struct Page: Decodable {
let pageid: Int
let title: String
let extract: String
}
}
So, key points:
If you don't know what keys would be there, use [String: <SomeDecodableType>] because any JSON Object can be mapped to the [String: <Decodable>].
You don't need to declare Page.Entry, just put all the fields to the Page
To get extract instead of entry.query.pages.first.extract you will have to use entry.query.pages.first?.value.extract (extract of first random page, because [String: Page] is unsorted) or entry.query.pages.sorted(by: sorter).first?.value.extract (where sorter is some function, that takes two key-value pairs and returns true if first one should go before second one in order) to get first using some order.
I have a custom class
public class Balance: NSObject {
var details: String
var date: Date
var amount: Double
}
I have tried as a struct and as a class both fail
I have an array of balances list: [Balance]
Now I'm need to convert this array into a JSON String
something like
[ {details = "text"; date = "2016-11-20"; amount = 0;} ,
{details = "text2"; date = "2016-11-25"; amount= 10;} ]
I also need to be able to convert the String back into the array.
But I can't even get the array to JSON string to work
var resStr = ""
var list: [Balance]
do {
let data = try JSONSerialization.data(withJSONObject: list, options: .prettyPrinted)
resStr = String.init(data: data, encoding: .utf8) ?? ""
} catch { fatalError("Error BALANCE HISTORY ") }
Fails with
'Invalid type in JSON write (Balance)'
Please advise
Thanks in advance
What about defining your class like this:
public class Balance: NSObject {
var details: String
var date: Date
var amount: Double
func toJSONString() -> String {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
return "{details = \(self.details); date = \(dateFormatter.string(from: self.date)); amount = \(self.amount);}"
}
}
Then you can create the full JSON string like this:
var fullJSONArray = [String]()
for balance in list {
fullJSONArray.append(balance.toJSONString)
}
let fullJSONString = fullJSONArray.description
I hope this helps you out! Good luck and let me know if you have any further questions or issues!
You can only store a quite small list of data types to JSON.
#CoolPenguin offers one solution - a custom method that will convert your object to a JSON string.
I would advise against building JSON strings yourself.
Instead, I would suggest creating a toDictionary() method for your class, and an init(dictionary:) method to create a Balance object from a dictionary.
You can convert the dates to TimeIntervals since 1970 (the UNIX "epoch date".) That seems easier than converting them to date strings.
You can then map your array of Balance objects to an array of dictionaries, and convert that to JSON using normal JSONSerialization.
let mappedArray = balanceArray.map{$0.toDictionary()}
And then easily convert your array of dictionaries to JSON.
Since others have pointed out that you can achieve the desired effect by first converting your object to a Dictionary, I will provide a method to achieve what is required by using JSONEncoder instead.
If you maintain the values you need to represent in the JSON encoded string (for example the date as a formatted String), the only required bits are,
Make your type conform to Codable
Create a CodingKeys enum that represent the JSON keys for your type's properties.
Please see below for an example that applies to your object.
public class Balance: NSObject, Codable {
var details: String
// Used to represent formatted date.
var dateString: String
var date: Date = Date(){
didSet{
updateDateString()
}
}
var amount: Double
enum CodingKeys: String, CodingKey{
case details, dateString, amount
}
init(_ d: String, amt: Double){
details = d
dateString = ""
date = Date()
amount = amt
super.init()
updateDateString()
}
private func updateDateString(){
let df = DateFormatter()
df.locale = Locale(identifier: "en_US_POSIX")
df.dateFormat = "yyyy-MM-dd"
dateString = df.string(from: date)
}
}
var arr: [Balance] = [
Balance("Shared Balance", amt: 100),
Balance("Coupon Balance", amt: 120),
Balance("Account Balance", amt: 150)
]
do{
let data = try JSONEncoder().encode(arr)
// Convert to JSON Encoded String
let str = String(data: data, encoding: .utf8)!
print(str)
// Convert back from JSON Encoded String
let raw = try JSONDecoder().decode([Balance].self, from: str.data(using: .utf8)!)
print(raw)
}
catch(let err){
print(err)
}
The additional updateDateString() boiler plate code is to produce the String with the date format, "yyyy-MM-dd".
The above code can product a JSON encoded version of your Balance array as follows.
[{"details":"Shared Balance","amount":100,"dateString":"2021-01-14"},
{"details":"Coupon Balance","amount":120,"dateString":"2021-01-14"},
{"details":"Account Balance","amount":150,"dateString":"2021-01-14"}]
The key takeaway is to use JSONEncoder instead of JSONSerialization.
Hope I helped!
Well, I believe first you need to convert your object to some form of dictionary.
Let me show you an example:
class Balance: NSObject {
var details: String
var date: Date
var amount: Double
func asDictionary() -> [String: AnyObject] {
return ["details": details as AnyObject, "date": "\(date)" as AnyObject, "amount": amount as AnyObject]
}
}
You use the method asDictionary to convert your objects to a dictionary so that you can serialize it into JSON.
Suppose you have a list of Balance objects.
You need to first convert each of those objects to dictionary using the method above, and then try to serialize the objects to JSON. Note that the list is now a list of [String: AnyObject] dictionaries, and not a list of Balance objects.
var resStr = ""
var list: [[String: AnyObject]] = [balance1.asDictionary(), balance2.asDictionary()]
do {
let data = try JSONSerialization.data(withJSONObject: list, options: .prettyPrinted)
resStr = String.init(data: data, encoding: .utf8) ?? ""
} catch { fatalError("Error BALANCE HISTORY ") }
For certain types, like the date field, you need to find some way to convert it to String, as the JSONSerializer is very picky. In this case I just used String interpolation, but the format may not be what you want it to be like.
If you want to convert back to a Balance object from JSON, first you need to get JSON into a dictionary, and then check for each field if it exists, and if so, construct your Balance object.
Supposing you have converted your JSON data into a dictionary in the variable named dict, you could do something like the following:
// supposing you have a single object in dict
var balance: Balance
balance.details = dict["details"]
balance.amount = dict["amount"]
balance.date = parseDate(dict["date"])
Supposing you have a function parseDate to parse the date from String into a Date object.
You can take a look here for converting String date into an object: Use SwiftyJSON to deserialize NSDate