CODEWITHSUNDEEP
swiftswitch-statement
jaykaydev
jaykaydev

Reputation: 141

How loop into an array and switch into its index

I have the array below:

let dict = [("Steve", 17),
             ("Marc", 38),
             ("Xavier", 21),
             ("Rolf", 45),
             ("Peter", 67),
             ("Nassim", 87),
             ("Raj", 266),
             ("Paul", 220),
             ("Bill", 392)]

How to loop through it and switch into the index in order to make operations in the three first, the three next and the last three.

Upvotes: 0

Views: 1237

Answers (4)

SwiftCoderVaibhav
SwiftCoderVaibhav

Reputation: 163

import Foundation
    
let dict = [("Steve", 17),
                ("Marc", 38),
                ("Xavier", 21),
                ("Rolf", 45),
                ("Peter", 67),
                ("Nassim", 87),
                ("Raj", 266),
                ("Paul", 220),
                ("Bill", 392)]
    for (index, (name, value)) in dict.enumerated() {
        switch index {
        case 0...2:
            // Operations for the first three elements
            print("\(name) is in the first group with value \(value)")
        case 3...5:
            // Operations for the next three elements
            print("\(name) is in the second group with value \(value)")
        case 6...8:
            // Operations for the last three elements
            print("\(name) is in the last group with value \(value)")
        default:
            // Handle any additional cases here
            break
        }
    }

Upvotes: 0

Tomasz Pe
Tomasz Pe

Reputation: 716

You could split your array by chunks of given size using Array extension:

extension Array {

    func chunked(by distance: IndexDistance) -> [[Element]] {
        return stride(from: startIndex, to: endIndex, by: distance).map {
            let newIndex = index($0, offsetBy: distance, limitedBy: endIndex) ?? endIndex
            return Array(self[$0 ..< newIndex])
        }
    }
}

And then use it like:

let splittedArrays = dict.chunked(by: 3)

splittedArrays.enumerated().forEach { index, subArray in
    switch index {
        case 0:
            //Do needed opertaions for the first group
            print("Players: \(subArray.map{$0.0}.joined(separator: ", "))")
        case 1, splittedArrays.endIndex - 1:
            //Do needed opertaions for the second and last group
            print("Result: \(subArray.map{$0.1}.reduce(0, +))")
        default:
            break
    }
}

Output:

Players: Steve, Marc, Xavier
Result: 199
Result: 878

Upvotes: 0

vacawama
vacawama

Reputation: 154583

You can use dict.enumerated() to get a sequence of (idx, item) tuples that for can then enumerate through. For example:

let dict = [("Steve", 17),
            ("Marc", 38),
            ("Xavier", 21),
            ("Rolf", 45),
            ("Peter", 67),
            ("Nassim", 87),
            ("Raj", 266),
            ("Paul", 220),
            ("Bill", 392)]

for (idx, item) in dict.enumerated() {
    let (name, value) = item

    switch (idx / 3) {
    case 0:
        print("\(name) is in the first group")
    case 1:
        print("\(name) is in the second group")
    case 2:
        print("\(name) is in the third group")
    default:
        print("\(name) not in first 3 groups")
    }

    print("value is \(value)")
}

Output:

Steve is in the first group
value is 17
Marc is in the first group
value is 38
Xavier is in the first group
value is 21
Rolf is in the second group
value is 45
Peter is in the second group
value is 67
Nassim is in the second group
value is 87
Raj is in the third group
value is 266
Paul is in the third group
value is 220
Bill is in the third group
value is 392

or equivalently, instead of doing integer math based upon the index, you could just switch on it directly but use a range for the cases:

switch idx {
case 0...2:
    print("\(name) is in the first group")
case 3...5:
    print("\(name) is in the second group")
case 6...8:
    print("\(name) is in the third group")
default:
    print("\(name) not in first 3 groups")
}

Upvotes: 1

pacification
pacification

Reputation: 6018

You can specify step of index by where clause:

for index in 0..<dict.count where index % 3 == 0 {
    // here you can do action with index, index + 1, index + 2 items in way you need
}

Upvotes: 0

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