Counting number of occurances in an Array - arrays

I want to count number of occurances in an array in ActionScript 3.0. Say I have
var item:Array = ["apples", "oranges", "grapes", "oranges", "apples", "grapes"];
How can I make it show the number of matching strings? For instance, result: apples = 2, oranges = 2 etc.
I got this code from another similar question:
private function getCount(fruitArray:Array, fruitName:String):int {
var count:int=0;
for (var i:int=0; i<fruitArray.length; i++) {
if(fruitArray[i].toLowerCase()==fruitName.toLowerCase()) {
count++;
}
}
return count;
}
var fruit:Array = ["apples", "oranges", "grapes", "oranges", "apples", "grapes"];
var appleCount=getCount(fruit, "apples"); //returns 2
var grapeCount=getCount(fruit, "grapes"); //returns 2
var orangeCount=getCount(fruit, "oranges"); //returns 2
In this code, if you want to get the count of say "apple". You need to set up variables for each item (var appleCount=getCount(fruit, "apples")). But what if you have hundreds and thousands of fruit names, it is not possible to write down new variables for each and every fruit.
I'm completely new to AS3 so forgive me. Please include clear comments in your code as I want to understand the code.

var item:Array = ["apples", "oranges", "grapes", "oranges", "apples", "grapes"];
//write the count number of occurrences of each string into the map {fruitName:count}
var fruit:String;
var map:Object = {}; //create the empty object, that will hold the values of counters for each fruit, for example map["apples"] will holds the counter for "apples"
//iterate for each string in the array, and increase occurrence counter for this string by 1
for each(fruit in item)
{
//first encounter of fruit name, assign counter to 1
if(!map[fruit])
map[fruit] = 1;
//next encounter of fruit name, just increment the counter by 1
else
map[fruit]++;
}
//iterate by the map properties to trace the results
for(fruit in map)
{
trace(fruit, "=", map[fruit]);
}
output:
apples = 2
grapes = 2
oranges = 2

Related

Count string elements in an array in a multidimensional array

I have an array that I populate from firestore that uses a struct. Is there a way to count the number of times there is a matching string for the productName var.
This is my struct...
struct PlayerStock: Codable, Identifiable {
#DocumentID var id: String?
var productName: String
var qty: Int
var saleUID: String
var totalPrice: Int
var uid: String
var unitPrice: Int
}
This is what's in my VC, I populate this from firestore and then want to count matching strings in productName
var playerStock: [PlayerStock] = []
Is there a way to do this without using a for loop?
Strings I'd like to count in productName include "smartphone" or "laptop" I want to store the matching total count as an int like this:
var smartphoneTotal =
var laptopTotal =
etc etc..
I've tried using filters and compact map but can't find anything that works, I think its because the array is multidimensional or because its using a dictionary?
Pretty noob here so any help appreciated!
First group the array by productName
let groupedProducts = Dictionary.init(grouping: playerStock, by: \.productName)
you'll get
["smartphone":[PlayerStock(..), PlayerStock(..), PlayerStock(..)],
"laptop":[PlayerStock(..), PlayerStock(..)]
then map the values to their amount of items
.mapValues(\.count)
The result is
["smartphone":3, "laptop":2]
If you want to use filter, something like this should work with your struct:
var laptopTotal = playerStock.filter { $0.productName == "laptop" }.count
This may help
let wordsToFind = ["smartphone", "laptop"]
var foundCounts: [String: Int] = [:]
for p in playerStock {
for word in wordsToFind {
if p.name.contains(word) {
foundCounts[word] = foundCounts[word, default: 0] + 1
}
}
}
foundCounts
If you really want a functional "no for-loops" version, and if you mean you want to find things that contain your search terms, then:
let wordsToFind = ["smartphone", "laptop"]
let founds = wordsToFind.map { word -> (String, Int) in
playerStock.reduce(("", 0)) { partialResult, player in
(word, partialResult.1 + (player.name.contains(word) ? 1 : 0))
}
}
You could use the higher order functions filter() or reduce(). #ShawnFrank already gave an answer using filter(). (voted.)
For a small number of items, there isn't a big difference between filter() and reduce(). For large datasets, though, filter creates a second array containing all the items that match the filter criteria. Arrays are value types, so they hold copies of the entries they contain. This would increase the memory footprint needed to do the counting. (You'd have the original array and a copy containing all the matching elements in memory).
The higher order function reduce() works differently. it takes a starting value (a total starting at 0 in our case) for the result, and a closure. The closure takes the current result, and an element from the array you are parsing. At runtime, the reduce() function calls your closure over and over, passing in each element from the array you are reducing. In the first call to the closure, it sends the closure the initial value for result (a zero total, in our case.) In each subsequent call to the closure, it passes the result of the previous call. (The running total, for our implementation.) The reduce() function returns the result returned by the last call to your closure.
You can use reduce to count the number of items that match a given test without having to build a temporary array. Below is a sample implementation using reduce(). Note that I tweaked your PlayerStock type to add default values for all the properties other than productName since I don't care about those.
// Define the PlayerStock type, but use default values for everything but `productName`
struct PlayerStock: Codable, Identifiable {
var id: String? = nil
var productName: String
var qty: Int = Int.random(in: 1...10)
var saleUID: String = ""
var totalPrice: Int = Int.random(in: 10...200)
var uid: String = ""
var unitPrice: Int = Int.random(in: 10...200)
}
// Create an array of test data
let players = [
PlayerStock(productName: "smartphone"),
PlayerStock(productName: "CD Player"),
PlayerStock(productName: "laptop"),
PlayerStock(productName: "CD Player"),
PlayerStock(productName: "smartphone"),
PlayerStock(productName: "laptop"),
PlayerStock(productName: "smartphone"),
PlayerStock(productName: "boom box"),
PlayerStock(productName: "laptop"),
PlayerStock(productName: "smartphone"),
]
/// This is a function that counts and returns the number of PlayerStock items who's productName property matches a the string nameToFind.
/// If you pass in printResult = true, it logs its result for debugging.
/// - Parameter nameToFind: The `productName` to search for
/// - Parameter inArray: The array of `PlayerStock` items to search
/// - Parameter printResult: a debugging flag. If true, the function prints the count if items to the console. Defaults to `false`
/// - Returns: The number of `PlayerStock` items that have a `productName` == `nameToFind`
#discardableResult func countPlayers(nameToFind: String, inArray array: [PlayerStock], printResult: Bool = false) -> Int {
let count = array.reduce(0, { count, item in
item.productName == nameToFind ? count+1 : count
})
if printResult {
print("Found \(count) players with productName == \(nameToFind)")
}
return count
}
let smartphoneCount = countPlayers(nameToFind: "smartphone", inArray: players, printResult: true)
let laptopCount = countPlayers(nameToFind: "laptop", inArray: players, printResult: true)
let cdPlayerCount = countPlayers(nameToFind: "CD Player", inArray: players, printResult: true)
This sample code produces the following output:
Found 4 players with productName == smartphone
Found 3 players with productName == laptop
Found 2 players with productName == CD Player

Merging arrays of dictionaries based on dates

I have 2 arrays, both of kind [[String:Any]] , where each element :
["date":Date,"value":CGFloat] //always looks like this
I might even have more than 2 (!)
I would like to create a single array with the same structure that sums all of them (2 or more) for each date that appears in all of them.
If the date of array1 does not appear on the others(array2, etc) I will simply add 0 to the value at array 1 for this specific date.
Is there a simple efficient way to do so ?
Instead of dictionaries use structs, it's more convenient:
struct MyStruct {
let date: Date
let value: CGFloat
}
Let's create 3 arrays of MyStructs:
let now = Date()
let later = now.addingTimeInterval(3600)
let earlier = now.addingTimeInterval(-3600)
let array1: [MyStruct] = [MyStruct(date: now, value: 1),
MyStruct(date: later, value: 2)]
let array2: [MyStruct] = [MyStruct(date: now, value: 3),
MyStruct(date: later, value: 4)]
let array3: [MyStruct] = [ MyStruct(date: earlier, value: 5),
MyStruct(date: later, value: 6)]
Now, let's group the elements and add the values for the elements with the same date property:
let allArrays = array1 + array2 + array3
let dict = Dictionary(allArrays.map { ($0.date, $0.value) },
uniquingKeysWith: { $0 + $1 })
All you have to do now is convert it back to an array of MyStruct:
let newArray = dict.map { MyStruct(date: $0.key, value: $0.value) }
And you can check the results like so:
for element in newArray {
print("date =", element.date, "value =", element.value)
}
I found a way, assuming data is inside a structure(not a dic) which is a better practice.
I will put all arrays into a single large array, sort it by dates, loop on it and as long as date is equal previous date(or close enough to equality), I will sum the values up. When the next date is different, I will save the date and the sum.
//create a combined array from all given arrays
var combined = [RootData]()
for list in dataSets {combined.append(contentsOf: list)}
//sort it by dates
let sortedArray = combined.sorted { $0.date < $1.date }
//new array - sum of all
var sumData = [RootData]()
var last:Date = sortedArray[0].date //set starting point
var sum:CGFloat = 0
for element in sortedArray
{
//same date - accumulate(same is less than 1 sec difference)
if(abs(element.date.seconds(from: last)) <= 1) {
sum+=element.value
}
//save
else {
sumData.append(RootData(value:sum,date:last))
sum=element.value
}
last=element.date
}
//last object
sumData.append(RootData(value:sum,date:last))
return averageData
Here RootData is a simple structure for the data with :
value:CGFloat
date:Date
Works as expected.
Because dates are not always completely equal , I check equality by assuming 1 second or less is the same date.

Change array string value from another array with index

I am trying to change my string value in an array after shuffling another array, how am i to do this?
Example:
var array1 = [1,2,3,4,5,6]
var stringarray = ["\\(array1[0]) = 1")
array1.shuffle()
print(stringarray)
How am i to change the original stringarray value to the new shuffled value?
Thank you
The task:
#IBAction func nextQuestion(_ sender: Any) {
if levelSelected == 1 {
questionLabel.text = standardRules.randomElement()
}
players.shuffle()
print(players)
standardRules has a string value that takes the value of players[0]
Essentially what i am trying to do is this:
I am trying to grab 2 random values that are not the same in a string like this
var players = ["Jack, John, Michael, Peter"]
var playersArray = ["\(players.randomElement) and \(players.randomElement) has to battle")
How am i to do this, so it grabs 2 different values?
You could make it very easy by this code :
var players = ["Jack", "John", "Michael", "Peter"]
// get the first random element
var random1 = players.randomElement()
//delete that element so you can't duplicate it
players = players.filter{$0 != random1}
//get your second radom element
var random2 = players.randomElement()
//add your element again
players.append(random1!)
Looks like you're missing some core concepts of the Swift language. When you create your stringarray it makes a call of array1.description and stores the result into an array. From that point any modifications of the original array will not change anything in stringarray.
So if you want to pick two different players from an array you need to do something like that:
let index1 = Int.random(in: (0 ..< players.count))
var index2: Int
repeat {
index2 = Int.random(in: (0 ..< players.count))
} while index1 == index2
let matchText = "\(players[index1]) and \(players[index2] has to battle)"
I would try replacing:
var stringarray = ["\\(array1[0]) = 1")
array1.shuffle()
with:
var stringarray = array1.shuffle()

Generate random Strings without a shuffle and repetition of previous ones?

My code already generates a random String of an array when I press a button, but sometimes a String gets repeated. What do I have to do so that the String "Mango" only gets called again when all the other Strings where already called without using a shuffle, I want to call one String at a time?
Example: "Mango", "Kiwi", "Banana", "Pineapple", "Melon", "Mango", "Kiwi",.....
Here is my code:
var array = ["Mango", "Banana", "Apple","Kiwi", "Melon", "Pineapple"]
let fruits = Int(arc4random_uniform(UInt32(array.count)))
print(array[fruits])
In order to avoid repetitions you need to keep track of which fruits have previously been seen. There are several ways to do that an all of the proposed solutions do it in one way or another.
For your specific use case, you will need this tracking to be retained outside of the code executed by the button (in your view controller for example).
Here is a generalized structure that could help with this:
(you can define it inside the view controller if this is a one-time thing or outside of it if you intend to reuse the mechanism elsewhere)
struct RandomItems
{
var items : [String]
var seen = 0
init(_ items:[String])
{ self.items = items }
mutating func next() -> String
{
let index = Int(arc4random_uniform(UInt32(items.count - seen)))
let item = items.remove(at:index)
items.append(item)
seen = (seen + 1) % items.count
return item
}
}
To use it, you would declare a variable (in your VC) that will keep track of your fruits:
var fruits = RandomItems(["Mango", "Banana", "Apple","Kiwi", "Melon", "Pineapple"])
And in the button's code use that variable (fruits) to print a non-repeating fruit name at each execution
func buttonPressed() // <- use your function here
{
print( fruits.next() )
}
You need to implement some logic. It's quite easy if you think harder. Run this in your Playground, or if you fully understand this block of code, you can do this in your project already.
var array = ["Mango", "Banana", "Apple","Kiwi", "Melon", "Pineapple"]
var selectedIndices = [Int]()
for _ in 1...20 {
let randomFruitIndex = Int(arc4random_uniform(UInt32(array.count)))
// Print only if not yet printed once
if !selectedIndices.contains(randomFruitIndex) {
print(array[randomFruitIndex])
selectedIndices.append(randomFruitIndex)
}
// Reset
if selectedIndices.count == array.count {
print("----- CLEARING SELECTED INDICES----")
selectedIndices.removeAll()
}
}
So as you can see, we are adding each generated random number (in your case, it's the fruits variable.) into an array of Int. Then if the number of selectedIndices is equal to the count of the array of fruits, clear all the stored selectedIndices.
OUTPUT:
Pineapple
Melon
Mango
Kiwi
Banana
Apple
----- CLEARING SELECTED INDICES----
Mango
Melon
This is an adaption from the accepted answer of the linked topic in my comment:
var source = ["Mango", "Banana", "Apple","Kiwi", "Melon", "Pineapple"]
var usedElements = [String]()
func choosePseudoRandomElement() -> String {
if source.count == 0 {
source = usedElements
usedElements = []
}
let randomIndex = Int(arc4random_uniform(UInt32(source.count)))
let randomItem = source[randomIndex]
usedElements.append(randomItem)
source.remove(at: randomIndex)
return randomItem
}
for _ in 1...18 {
print("Item: \(choosePseudoRandomElement())")
}
One potential issue with this solution is that it may happen, that the last element of one complete iteration also occurs as the first element of the second iteration. You can handle that case by comparing the randomly chosen item with the item which was chosen before (use a while loop until the items doesn't match anymore).
Also, this does remove elements from the source array. If you do not want that, create a copy of the source array.

AS3: Sort array descending while keeping strings in correct order

I'm not sure whether there is a simply answer to this but I am assuming there isn't, hence I'm here.
Basically, I want to run a very simple high score table which keeps track of the high scores of a game, but also displays the correct names beside each scores.
This is all easy but I want to be able to do this with just the one array.
For example, I have this code:
var d:Array;
var e:Array;
d = "827-Harry".split("-");
d.push("918-John".split("-"));
trace(d)
Which correctly results this trace:
827,Harry,918,John
My question is, how can I use Array.sort() (or similar) in such a way that the following is produced:
d = 918, John, 827, Harry
It can't be specific to this example. That is, it needs to work with custom names and dynamic scores.
Cheers in advance!
Harry.
create an associative array and use sortOn():
var highscores:Array = new Array();
highscores.push({score: 827, player: "John"});
highscores.push({score: 918, player: "Harry"});
highscores.sortOn("score", Array.DESCENDING | Array.NUMERIC);
for (var i:int = 0; i < highscores.length; i++)
{
trace(highscores[i].score, highscores[i].player);
}
Wouldn't recommend you store your high scores like that but I don't know your reasons so here's exactly how to do what you want.
public function sortArray(arrUnsorted:Array):Array
{
var arrLocal:Array = new Array();
var arrSorted:Array = new Array();
for (var i:int = 0; i < arrUnsorted.length; i += 2)
{
arrLocal.push( { score:int(arrUnsorted[i]), name:arrUnsorted[i + 1] } );
}
arrLocal.sortOn("score", Array.DESCENDING | Array.NUMERIC)
for each(var obj:Object in arrLocal)
{
arrSorted.push(String(obj.score), obj.name);
}
return arrSorted;
}
Then it's as simple as:
var arrUnsorted:Array = ["827", "Harry", "918", "John"];
var arrSorted:Array = sortArray(arrUnsorted);
trace(arrSorted); // 918,John,827,Harry
Hope this is what you're after.

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