I want to sum the "quantity" values of all files, but the decimal point is not read, only the integer is added, why is this?
func getDatas2(){
self.db.collection("Admin").document("AI智能機器人").collection("Ai日獲利").getDocuments { snapshot, error in
if error != nil {
print(error?.localizedDescription ?? "Error while getting data from server!" )
}else{
if snapshot?.isEmpty != true && snapshot != nil {
for document in snapshot!.documents{
if let quantity = document.data()["quantity"] as? Int{
self.totalVotes += quantity
self.new.text = "\(self.totalVotes)"
}
}
}
}
}
}
Here's my current function that sums integers fine, values with decimal points don't read.
values with decimal points don't read
That is happening because you're casting a decimal number field type to an Int rather than to double:
if let quantity = document.data()["quantity"] as? Int
Int is a type of number that doesn't store decimal numbers. So to solve this you have to cast the value that you're reading from Firestore into a double like this:
if let quantity = document.data()["quantity"] as? Double
// 👆
Related
I'm attempting to get a user input number and find the sum of all the digits. I'm having issues with larger numbers, however, as they won't register under an Int64. Any idea as to what structures I could use to store the value? (I tried UInt64 and that didn't work very well with negatives, however, I'd prefer something larger than UInt64, anyways. I'm having a hard time implementing a UInt128 from Is there a number type with bigger capacity than u_long/UInt64 in Swift?)
import Foundation
func getInteger() -> Int64 {
var value:Int64 = 0
while true {
//we aren't doing anything with input, so we make it a constant
let input = readLine()
//ensure its not nil
if let unwrappedInput = input {
if let unwrappedInt = Int64(unwrappedInput) {
value = unwrappedInt
break
}
}
else { print("You entered a nil. Try again:") }
}
return value
}
print("Please enter an integer")
// Gets user input
var input = getInteger()
var arr = [Int] ()
var sum = 0
var negative = false
// If input is less than 0, makes it positive
if input < 0 {
input = (input * -1)
negative = true
}
if (input < 10) && (input >= 1) && (negative == true) {
var remain = (-1)*(input%10)
arr.append(Int(remain))
input = (input/10)
}
else {
var remain = (input%10)
arr.append(Int(remain))
input = (input/10)
}
}
// Adds numbers in array to find sum of digits
var i:Int = 0
var size:Int = (arr.count - 1)
while i<=size {
sum = sum + arr[i]
i = (i+1)
}
// Prints sum
print("\(sum)")
You can use a string to perform the operation you describe. Loop through each character and convert it to an integer and add to the sum. Be careful to handle errors.
This question already has answers here:
Refactored Solution In Swift
(2 answers)
Closed 6 years ago.
I'm attempting to solve HackerRank's Hash Table Ransom Note challenge. There are 19 test cases and I'm passing all but two of time due to timeout on larger data sets (10,000-30,000 entries).
I'm given:
1) an array of words contained in a magazine and
2) an array of words for a ransom note. My objective is to determine if the words in the magazine can be used to construct a ransom note.
I need to have enough unique elements in the magazineWords to satisfy the quantity needed by noteWords.
I'm using this code to make that determination...and it takes FOREVER...
for word in noteWordsSet {
// check if there are enough unique words in magazineWords to put in the note
if magazineWords.filter({$0==word}).count < noteWords.filter({$0==word}).count {
return "No"
}
}
What is a faster way to accomplish this task?
Below is my complete code for the challenge:
import Foundation
var magazineWords = // Array of 1 to 30,000 strings
var noteWords = // Array of 1 to 30,000 strings
enum RegexString: String {
// Letters a to z, A to Z, 1 to 5 characters long
case wordCanBeUsed = "([a-zA-Z]{1,5})"
}
func matches(for regexString: String, in text: String) -> [String] {
// Hat tip MartinR for this
do {
let regex = try NSRegularExpression(pattern: regexString)
let nsString = text as NSString
let results = regex.matches(in: text, range: NSRange(location: 0, length: nsString.length))
return results.map { nsString.substring(with: $0.range)}
} catch let error {
print("invalid regex: \(error.localizedDescription)")
return []
}
}
func canCreateRansomNote(from magazineWords: [String], for noteWords: [String]) -> String {
// figure out what's unique
let magazineWordsSet = Set(magazineWords)
let noteWordsSet = Set(noteWords)
let intersectingValuesSet = magazineWordsSet.intersection(noteWordsSet)
// constraints specified in challenge
guard magazineWords.count >= 1, noteWords.count >= 1 else { return "No" }
guard magazineWords.count <= 30000, noteWords.count <= 30000 else { return "No" }
// make sure there are enough individual words to work with
guard magazineWordsSet.count >= noteWordsSet.count else { return "No" }
guard intersectingValuesSet.count == noteWordsSet.count else { return "No" }
// check if all the words can be used. assume the regex method works perfectly
guard noteWords.count == matches(for: RegexString.wordCanBeUsed.rawValue, in: noteWords.joined(separator: " ")).count else { return "No" }
// FIXME: this is a processor hog. I'm timing out when I get to this point
// need to make sure there are enough magazine words to write the note
// compare quantity of word in magazine with quantity of word in note
for word in noteWordsSet {
// check if there are enough unique words in magazineWords to put in the note
if magazineWords.filter({$0==word}).count < noteWords.filter({$0==word}).count {
return "No"
}
}
return "Yes"
}
print(canCreateRansomNote(from: magazineWords, for: noteWords))
I don't know how to read from the test case on the contest website or what frameworks you are allowed. If Foundation is allowed, you can use NSCountedSet
import Foundation
let fileContent = try! String(contentsOf: URL(fileURLWithPath: "/path/to/file.txt"))
let scanner = Scanner(string: fileContent)
var m = 0
var n = 0
scanner.scanInt(&m)
scanner.scanInt(&n)
var magazineWords = NSCountedSet(capacity: m)
var ransomWords = NSCountedSet(capacity: n)
for i in 0..<(m+n) {
var word: NSString? = nil
scanner.scanUpToCharacters(from: .whitespacesAndNewlines, into: &word)
if i < m {
magazineWords.add(word!)
} else {
ransomWords.add(word!)
}
}
var canCreate = true
for w in ransomWords {
if ransomWords.count(for: w) > magazineWords.count(for: w) {
canCreate = false
break
}
}
print(canCreate ? "Yes" : "No")
It works by going through the input file one word at a time, counting how many times that word appears in the magazine and in the ransom note. Then if any word appear more frequently in the ransom note than in the magazine, it fails the test immediately. Run the 30,000 words test case in less than 1 second on my iMac 2012.
I have parser in Objc, parser returns NSDictionary. I am using this parser in swift class. But when some value is missing on that dictionary, it shows nil value. e.g. ->
wirlessData = {
"anon" = {
};
"channel" = {
"text" = 1;
};
}
I am checking through
if let wepauthValue = wirlessData["wepauth"] {
if let value = wepauthValue["text"] {
print("\(value)") // nil
}
}
I don't how it satisfy the if let condition. Any one faced this types of problem can help me out.
Thanks,
vikash
You don't need any special code to do this, because it is what a dictionary already does. When you fetch dict[key] you know whether the dictionary contains the key, because the Optional that you get back is not nil (and it contains the value).
So, if you just want to answer the question whether the dictionary contains the key, ask:
let keyExists = dict[key] != nil
If you want the value and you know the dictionary contains the key, say:
let val = dict[key]!
But if, as usually happens, you don't know it contains the key - you want to fetch it and use it, but only if it exists - then use something like if let:
if let val = dict[key] {
// now val is not nil and the Optional has been unwrapped, so use it
}
I have tested it and found that value is still optional.Take a look at screenshot below to understand it better.
"anon" would be an empty dictionary. An empty dictionary is not nil, it is a dictionary. Just an empty one. A JSON parser will never, ever give nil values unless you ask for a key that is not in a dictionary. For example wirlessData ["nonexistingkey"] would give you nil.
If you be more type-strong about it with the if..let's then:
if let anonValue = wirlessData["anon"] {
if let value = anonValue["text"] as? String {
// This won't execute if value isn't converted from `anonvalue["text"]` to String specifically. This includes null been a false match too
print("\(value)") // nil
}else{
print("Value did't match string at all")
}
}
or even more specifically in your case:
if let anonValue = wirlessData["anon"] {
if let value = anonValue["text"] as? Int {
// This won't execute if value isn't converted from `anonvalue["text"]` to String specifically. This includes null been a false match too
print("\(value)") // nil
}else{
print("Value did't match int at all")
}
}
The value your parser is returning not nil, its empty so you need to check on count if inner data type is dictionary or array, I have past 1 sample here
Please use below code and correct your logic accordingly to get it work properly
let wirlessData:[String:AnyObject] = [
"anon" : [],
"channel" : [
"text" : 1
]
]
if wirlessData["anon"]?.count > 0 {
if let value = wirlessData["anon"]!["text"] {
print("\(value)") // nil
}
}
Try this below code using type check operator (is) -
if wirlessData["anon"] is [String:AnyObject]
{
let anon = wirlessData["anon"]!
print(anon)
if anon["random"] is String {
let stringValue = anon["random"]!
print("\(stringValue)")
}
else if anon["random"] is Int
{
let intValue = anon["random"]!
print("\(intValue)") // nil
}
else
{
print(" may be value did't match string & Int or nil ")
}
}
I am trying to Multiply
self.tipLable.text = String("\((enterBillAmountTextField.text! as NSString).integerValue * (middleTextField.text! as NSString).integerValue * (0.01))")
But getting error Binary operator * cannot be applied to operands of type Int and Double
I am taking values form UITextfields. How to do this multiplication?
extension Double {
// Convert Double to currency
var currency: String {
let formatter = NSNumberFormatter()
formatter.numberStyle = .DecimalStyle
formatter.maximumFractionDigits = 2
formatter.minimumFractionDigits = 2
return formatter.stringFromNumber(self) ?? "0"
}
}
tipLable.text = [enterBillAmountTextField, middleTextField].reduce(0.01) { $0 * (Double($1.text!) ?? 0) }.currency
A slightly shorter and clearer solution. Added a "currency" extension so it can still be done in one line :).
This works
self.tipLable.text = String("\( Double((enterBillAmountTextField.text! as NSString).integerValue) * Double((middleTextField.text! as NSString).integerValue) * 0.01)")
Swift doesn't know how to multiply an Int and a Double. Should the result be an Int or a Double?
Swift won't do implicit type conversion between different operands.
If you want your result to be a Double, both operands should be a Double. Then convert the Double to a String.
While this can all be concisely expressed in one single very long line, perhaps it's more readable and maintainable if you break it out into separate lines:
let subTotal = Double(billAmountTextField.text!) ?? 0
let percent = (Double(middleTextField.text!) ?? 0) * 0.01
let tip = subTotal * percent
self.tipLable.text = String(format: "%.2f", tip) // Handle rounding
The answer you gave is going to bring nightmare to you in some moment.
Try to keep yourself doing things in a way you can guarantee that you are going to be able to test it and that you/or others are going to be able to understand what you are doing there.
/**
Use this function to calculate tip, useful for later testing
- returns: Double Value of the tip you should give
*/
func calculateTip(billAmount billAmount:Double, middleValue:Double) -> Double {
/// Actually calculate Tip if everything is OK
return billAmount * middleValue * 0.01
}
Then in your #IBAction make sure you have correct data before asking
your function for a tip
/// If you have bill data, obtain Double value stored there,
/// if something fails, you should return nil
guard let billAmountText = enterBillAmountTextField.text, billAmount = Double(billAmountText) else {
return
}
/// If you have middle value data, obtain Double value stored there,
/// if something fails, you should return nil
guard let middleText = middleTextField.text, middleValue = Double(middleText) else {
return
}
Then you can call that function
let tip = calculateTip(billAmount: billAmount, middleValue: middleValue).description
//and return in proper format
tipLabel.text = String(format: "%.2f", tip)
I have two orgunit_id's, test["orgunit_id"] and API.loginManagerInfo.orgUnit, which I would like to compare. The problem is that the variables have different types. test["orgunit_id"] is value of a NSDictionary and the other one is a String.
I've tried several ways to cast it into Integers, but without success.
Code:
if(!orgUnits.isEmpty){
print(orgUnits) //See at console-output
for test: NSDictionary in orgUnits {
println(test["orgunit_id"]) //See at console-output
println(API.loginManagerInfo.orgUnit) //See at console-output
if(Int(test["orgunit_id"]? as NSNumber) == API.loginManagerInfo.orgUnit?.toInt()){ // This condition fails
...
}
}
}
Output:
[{
name = Alle;
"orgunit_id" = "-1";
shortdescription = Alle;
}, {
name = "IT-Test";
"orgunit_id" = 1;
shortdescription = "";
}]
Optional(-1)
Optional("-1")
Edit:
Here's the definition of API.loginManagerInfo.orgUnit: var orgUnit:String?
Use if let to safely unwrap your values and typecast the result.
If test["orgunit_id"] is an Optional Int and if API.loginManagerInfo.orgUnit is an Optional String:
if let testID = test["orgunit_id"] as? Int, let apiIDString = API.loginManagerInfo.orgUnit, let apiID = Int(apiIDString) {
if testID == apiID {
// ...
}
}
You may have to adapt this example given what is in your dictionary, but you get the point: safely unwrap the optional value and either typecast it (with if let ... = ... as? ...) or transform it (with Int(...)) before comparing.