I am downloading information from a Firebase database and it is being inputted via a for loop into:
static var Reports = [String:[String:String]]()
I need to figure out a way to search the inside values for a certain string
I have messed around with this but can't seem to get it inside the inside dictionary (If that makes sense)
for values in Reports.count {
if let item = Reports["favorite drink"] {
print(item)
}
}
I need to have a search string then a number of times the value appears like so:
func findString(dict Dictionary) -> Int {
var ReportsLevel1 = 0
(for loop I'm guessing)
search here for string
return ReportsLevel1
}
Tip: the outside dictionary keys are not set in stone, they depend on what time and date the report was submitted
To find out the numberOfTimes in which "yourSearchString" appears you can do as follows
var numberOfTimes = 0
for internalDictionary in reports.values
{
for value in internalDictionary.values
{
if (value == "yourSearchString") { numberOfTimes += 1 }
}
}
or
let numberOfTimes = reports.flatMap { internalDictsArray in internalDictsArray.value.filter { $0.value == "yourSearchString" } }.count
Related
I’ve got multiple variables with the same name but a different number on the end like this:
MyVar1, MyVar2, MyVar3, MyVar4
and they are either true or false
How do I write this correctly?
For index in Range(1...4){
if (“MyVar” + index) == true{
print(“:)”)
}
}
didnt tries the solution but according to this post: https://stackoverflow.com/a/45622489/5464805 you can do this:
Edit: I read that your variables are Booleans
for i in 0...4 {
if let var = myObject.value(forKey: "MyVar\(i)") as Bool,
var { // If var is successfully cast and true it enters the statement
print(var)
}
}
HOWEVER
All the other solutions above or below are still correct. This is something you dont usually do in Swift in general unless you must do so.
You should either rewrite your model and give a proper name to each variables, that you will later put into an array such as...
class MyObject {
var MyVar1: Bool // To Rename
var MyVar2: Bool // To Rename
var MyVar3: Bool // To Rename
var MyVars: [Bool] {
get { return [MyVar1, MyVar2, MyVar3] }
}
}
Or you completely get rid of these variable and create an Array directly
class MyObject {
// var MyVar1: Bool // To Delete
// var MyVar2: Bool // To Delete
// var MyVar3: Bool // To Delete
var MyVars: [Bool]
}
and you set the Array / Dictionnary in accordance to your needs
You are trying to get a sum of String ("MyVar") and Int ("index") and compare that sum with Bool (true)
It would be more safety to store all your variables in an array like that
let myVars = [MyVar1, MyVar2, MyVar3, MyVar4]
Then you can iterate throught the array:
for i in myVars {
if i {
print(i)
}
}
You can't create a variable from concatenation at runtime , you need to have an array of bool like this
var arr = [false,true,true,false] // var1 , var2 , var3 , var4
for item in arr {
if item {
}
}
This is a little hard to explain, but I'll try my best. I am trying to update a Dictionary inside another Dictionary properly. The following code almost does what I need.
var dictionary = Dictionary<String, [Int : Int]>()
func handleStatsValue(tag: Int ) {
let currentValue: Int = dictionary["Score"]?[tag] ?? 0
dictionary["Score"] = [
tag : currentValue + 1
]
}
However, it seems the dictionary is overridden when the tag value changes (e.g. 1 to 2). I need Dictionary to have multiple dictionaries inside of it. Any tips or suggestions are deeply appreciated.
Edit: I'm trying to have multiple dictionaries nested inside a dictionary. It seems whenever the tag value is changed, the dictionary is overridden.
One way to write this would be:
func handleStatsValue(tag: Int) {
dictionary["Score", default: [:]][tag, default: 0] += 1
}
or, written without [_:default:]
func handleStatsValue(tag: Int) {
var scoreDictionary = dictionary["Score"] ?? [:]
scoreDictionary[tag] = (scoreDictionary[tag] ?? 0) + 1
dictionary["Score"] = scoreDictionary
}
However, it's not a good idea to use nested dictionaries to keep your data. Use a custom struct instead and try to avoid tags too:
struct DataModel {
var score: [Int: Int] = [:]
}
I think you need something like this to either increase the value for an existing tag or add a new tag if it doesn't exist
func handleStatsValue(tag: Int ) {
if var innerDict = dictionary["Score"] {
if let value = innerDict[tag] {
innerDict[tag] = value + 1
} else {
innerDict[tag] = 1
}
dictionary["Score"] = innerDict
}
}
Although the code looks a bit strange with the hardcoded key "Score", maybe it would be better to have multiple simple dictionaries instead, like
var score: [Int, Int]()
or if you prefer
var score = Dictionary<Int, Int>()
class Employee{
var id:Int
var name:String
var salary:Int
init(){
self.id=0
self.name=""
self.salary=0
}
func getInfo(){
self.name=readLine()!
self.id=Int(readLine()!)!
self.salary=Int(readLine()!)!
}
}
var count=0
var flag="y"
var empData:[Employee]=[]
repeat{
count+=1
empData[count]=Employee()
empData[count].getInfo()
flag=readLine()!
}while(flag=="y") `
I have a class Employee with properties id , nam and salary. The function getInfo() is used to get information from user. I want to read data until the flag!="y" . I am getting index out of range error.
What is the right way of inputting data? Can we index the objects ?
You need to append to your array to make it increase in size. Replace
empData[count]=Employee()
with
empData.append(Employee())
to avoid index out of range error
Update
To make your code a little less horrible I would do
repeat {
var employee = Employee()
employee.getInfo()
empData.append(employee)
flag=readLine()!
}while( flag == "y" )
The subscript operator cannot be used to add elements to an array index which doesn't exist yet. You either need to initialize the array with an element count if you know at the time of initialization how many elements your array will have or use the append operator to add new elements to the array after the last index.
You don't even need the count variable, as you can simply access empData.last safely after calling append and adding a new Employee to the Array.
var flag="y"
var empData:[Employee]=[]
repeat {
empData.append(Employee())
empData.last!.getInfo()
flag=readLine()!
} while(flag=="y")
I would advise you to seriously reconsider your implementation as it is really unsafe at the moment. You are not validating user input in any way, hence your getInfo function can easily cause runtime errors if the user input is not in the expected form. Moreover, creating an empty initializer for Employee doesn't make sense, you could simply create a failable initializer, where you read the input and if the input is not of the correct form, make the initializer return nil.
class Employee{
let id:Int
let name:String
let salary:Int
init?(){
guard let name = readLine() else { return nil }
self.name = name
guard let idString = readLine(), let id = Int(idString) else { return nil }
self.id = id
guard let salaryString = readLine(), let salary = Int(salaryString) else { return nil}
self.salary = salary
}
}
var flag="y"
var empData:[Employee]=[]
repeat {
if let employee = Employee() {
empData.append(employee)
} else {
// Display error message to the user
}
flag=readLine() ?? ""
} while(flag=="y")
I was wondering if there's a way to step through a dictionary in Swift. I know I can iterate through, but I was hoping to step one by one through a dictionary of items as the user taps a "next" button.
I was thinking I could initially iterate through the dictionary and store the keys in an array, then step through the keys and retrieve each item as needed, since the array can be indexed. This seems a little inelegant, though. Any thoughts?
My current approach:
var iterator = 0
var keys = [String]()
func loadKeys() {
for (key, value) in items {
keys.append(key)
}
}
func step() {
iterator += 1
let currentKey = keys[iterator]
let currentItem = items[currentKey]
}
I figure it would work just fine, just not sure it's the best practice.
Thanks for your help!
A dictionary also provides you with an iterator, so you can step through it using that:
var iterator = items.makeIterator()
func step() {
if let v = iterator.next() {
let currentKey = v.key
let currentValue = v.value
}
}
A dictionary is an indexed collection, so you can use a dictionary's index to step through the keys and values:
var i = items.startIndex
func step() {
guard i != items.endIndex else {
// at the end of the dictionary
return
}
let (currentKey, currentValue) = items[i]
i = items.index(after: i)
}
Trying to build a rating system in Swift and looking for a cleaner way to loop through each of the values.
private func calculateRating(user: String) throws -> String {
let query = try Rating.makeQuery().filter("user", user).all()
var fiveStars = [Int]()
var fourStars = [Int]()
var threeStars = [Int]()
var twoStars = [Int]()
var onestar = [Int]()
if query.count > 1 {
for rating in query {
// Check each value and assign it to its associated value
// insert large if/else condition here :)
}
// Perform calculation and return value below
return ""
} else {
// Only one rating has been set
return query[0].value
}
}
Currently I'm looping through each of the values and assigning the rating to it's associated array fiveStars fourStars etc. I will then calculate the rating by the standard multiplication method. Is there a cleaner way to loop through the ratings and assign it to the relevant fiveStars array etc without creating a long if/else conditional?
Thanks
Edit: Sample output would be a single rounded up value out of 5 i.e. "4" out of five based on 1000's of multiple ratings.
let twoStars: [Int] = query.filter {$0.val == 2} .map {$0.val}
And so on.