how to for loop increment in swift 4?

Question

krishnaamen OP

Created Nov ’17

Replies 3

Boosts 0

Views 7.5k

Participants 4

my for loop increment is not working properly.

import UIKit

class ViewController: UIViewController {

@IBOutlet var Label1: UILabel!

@IBOutlet var Label2: UILabel!

@IBOutlet var textField: UITextField!

@IBOutlet var Label3: UILabel!

let alert = "you are wrong"

let correct = "you are right"

let enWord = ["delever","warn","work","love"]

let dkWord = ["afleverer","advarer","arbejder","elsker"]

override func viewDidLoad() {

super.viewDidLoad()

Label2.text = enWord[0]

}

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

/

}

@IBAction func Clicked(_ sender: Any) {

let answer = textField.text

for i in stride(from: 0, to: 4, by: 1) {

Label2.text = enWord[i]

if (answer == dkWord[i]){

}

else {

print("next")

}

Boost

Answer 1

KMT OP

Nov ’17

>how to for loop

That code smells severely outdated/not Swift 4.

Go here and look at 'for-in' loops, instead:

https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/ControlFlow.html

0

Answer 2

Claude31 OP

Nov ’17

what doesn’t work ?

you do nothing if == succeeds. What do you expect ?

a simpler form would be (even though stride is OK)

    @IBAction func clicked(_ sender: Any) {     // start func name with lowercase
        let answer = textField.text
        for i in 0..<4 {
        Label2.text = enWord[i]
        if (answer == dkWord[i]){
              // do something and probably return after
            }
            else {
                print("next")
            }
    }

0

Answer 3

DTS Engineer OP

Apple

Nov ’17

Or you could avoid array indexing entirely:

for (en, dk) in zip(enWord, dkWord) {
    print(en, dk)
}

I’ve started writing my code this way because it means I don’t have to worry about accessing the array out of bounds. And once you start down this path you might think about using a higher-level algorithm (like

first(where:)

) rather than a vanilla

for

loop. For example:

guard let en = zip(enWord, dkWord).first(where: { $1 == answer })?.0 else {
    … handle the not found case …
    return
}
… handle the found case …

Alternatively, you could avoid the loop entirely by pre-processing

enWord

and

dkWord

into a dictionary that maps one to the other:

let dkToEn = Dictionary(uniqueKeysWithValues: zip(dkWord, enWord))

at which point you can search using a dictionary lookup:

guard let en = dkToEn[answer] else {
    print("-not found-")
    return
}
print(en)

The drawback to this last approach is that you don’t control the compare function so, for example, you can’t do a case insensitive compare (you could canonicalise

answer

before doing the lookup but that may not cover all the necessary edge cases).

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