How to create numbered list from tuples array?-CodePudding

I have the following list:

   let myList: [(String, Int, Double)] = [("A", 1, 1.5), ("B", 2, 2.5), ("C", 3, 3.5)]

And I am trying to produce the following output

1) A | 1
2) B | 2
3) C | 3

If I delete the 2nd element I want the output to be updated as well, like this

1) A | 1
2) C | 3

I'm new to Swift, so this is a lot to wrap my head around but how would I start something like this? This is my function, but I am not sure if this is the right way to start. And I'm wondering how I can get the extra symbols and keep the numbers in order. ( this value is going to be passed to a UILabel, so I have to keep all the elements together in one variable result)

func displayString(myList: [(title: String, id: Int, value: Double)]) -> String {

   var result = ""

   for i in 0..<myList.count {
     
    
    
   }

 

   return result 
 }

CodePudding user response：

If you need the 1) and 2) as well on every line, have a look at looping through arrays using enumerated where you have access to the index as well as the item

It would look something like this:

func displayString(myList: [(title: String,
                                   id: Int,
                                   value: Double)]) -> String
{
    var result = ""
    
    // The first iteration, index is 0 and item is ("A", 1, 1.5)
    // Second time, index is 1 and item is ("B", 2, 2.5) etc
    for (index, item) in myList.enumerated()
    {
        // Since index starts from 0, you add  1 to start from 1 in the output
        result  = "\(index 1)) \(item.title) | \(item.id)\n"
    }
    
    return result
}

The output would be:

1) A | 1
2) B | 2
3) C | 3

However, I urge you to explore higher order functions like filter, map, reduce etc which will shorten the code you write to do these things.

For example, you could get a similar result with something like:

func displayStringSwifty(myList: [(title: String,
                                   id: Int,
                                   value: Double)]) -> String
{
    return myList.reduce("") { val, item in val   "\(item.0) | \(item.1)\n" }
}

The output would be

A | 1
B | 2
C | 3

As a challenge and practice, you could try to use the second option to create the output similar to the first with the 1), 2) etc added as well

CodePudding user response：

let myList: [(String, Int, Double)] = [
             ("A", 1, 1.5),
             ("B", 2, 2.5),
             ("C", 3, 3.5)]

myList.enumerated().forEach { (index, element) in
    print( "\(index 1)) \(element.0) | \(element.1)" )
}

gives you

1) A | 1
2) B | 2
3) C | 3