[swift-users] Simplify chained calls

[Adriano Ferreira]

Hi Tod, thanks for sharing your ideas. Much appreciated!

Feel free to take a look at my playground where I explore many other alternative implementations.

https://github.com/adrfer/Sort/tree/swift-3

Best,

— A

> On Jun 30, 2016, at 11:32 AM, Tod Cunningham via swift-users <swift-users at swift.org> wrote:
> 
> This was bugging me last night, as I still didn’t like the solution.  What about something like:
> 
> func selectionSort(_ originalArray: [Int]) -> [Int] {
>    var array = originalArray
>    for index in 0..<array.count {
>        let minIndex = array.indices.clamped(to: index..<x.count).min(isOrderedBefore: { array[$0] < array[$1] })
>        if index != minIndex {
>            swap(&array[index], &array[minIndex!])
>        }
>    }
>    return array
> }
> 
> 
> 
> On 6/29/16, 7:12 PM, "swift-users-bounces at swift.org on behalf of Tod Cunningham via swift-users" <swift-users-bounces at swift.org on behalf of swift-users at swift.org> wrote:
> 
> Was trying to using some functional programming concepts while also using as little memory as possible.  The big advantage of using a selections sort is that it sorts w/o having to allocation additional memory.  This still violates that, but it’s closer.  :)
> 
> func selectionSort(_ array: inout [Int]) {
>    for index in 0..<array.count {
>        // .1 is value .0 is the index on the enumeration
>        let minElement = array.enumerated().dropFirst(index).min(isOrderedBefore: { $0.1 < $1.1 } )
>        if index != minElement!.0 {
>            swap(&array[index], &array[minElement!.0])
>        }
>    }
> }
> 
> or using recursion:
> 
> func selectionSort(_ array: inout [Int], index: Int = 0) {
>    if index < array.count {
>        // .1 is value .0 is the index on the enumeration
>        let minElement = array.indexed().dropFirst(index).min(isOrderedBefore: { $0.1 < $1.1 } )
>        if index != minElement!.0 {
>            swap(&array[index], &array[minElement!.0])
>        }
>        selectionSort(&array, index: index+1)
>    }
> }
> 
> 
> 
> On 6/28/16, 10:58 PM, "swift-users-bounces at swift.org on behalf of Erica Sadun via swift-users" <swift-users-bounces at swift.org on behalf of swift-users at swift.org> wrote:
> 
>> 
>> On Jun 28, 2016, at 8:18 PM, Dan Loewenherz via swift-users <swift-users at swift.org> wrote:
>> 
>> I’m not sure if you wanted to stick with the pure functional approach, but here’s an alternative that uses Range<Int> to take care of most of the work.
>> 
>> func selectionSort(_ array: [Int]) -> [Int] {
>>    guard let minValue = array.min(), let index = array.index(of: minValue) else {
>>        return []
>>    }
>> 
>>    let ranges = [0..<index, index.advanced(by: 1)..<array.endIndex]
>>    return [minValue] + selectionSort(ranges.flatMap { array[$0] })
>> }
>> 
> 
> Most everyone is doing two passes, one to get the minimum value, another to get its index.
> I aesthetically prefer using enumerate to do both at once.
> 
> -- E
> 
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