How can I find the highest elements of an Array in Swift?

问题

Can someone please explain how one would get the highest elements of an array in Swift 2.2?

For example lets say I have this code:

let myArray: [Int] = [2, 1, 6, 3, 5 ,7, 11]

How would i retrieve the 3 highest values of that array? In this case I'd want the numbers 6, 7 and 11.

Any help would be greatly appreciated.

回答1:

To find the 3 highest items, sort the array and take the last 3 items using suffix:

let myArray = [2, 1, 6, 3, 5 ,7, 11]
let highest3 = myArray.sort().suffix(3)
print(highest3)  // [6, 7, 11]

For the 3 lowest items, use prefix:

let lowest3 = myArray.sort().prefix(3)
print(lowest3)  // [1, 2, 3]

prefix and suffix have the added advantage that they do not crash if your array has fewer than 3 items. An array with 2 items for instance would just return those two items if you asked for .suffix(3).

回答2:

let highestNumber = myArray.maxElement()

Shown in playground

Edit: Sorry, didn't read the full question, this method only retrieves the one highest value, here is a reconfigured version that should work

let myArray: [Int] = [2, 1, 6, 3, 5 ,7, 11, 4, 12, 5]
var myArray2 = myArray
var highestNumbers: [Int] = []

while highestNumbers.count < 3 {
    highestNumbers.append(myArray2.maxElement()!)
    myArray2.removeAtIndex(myArray2.indexOf(myArray2.maxElement()!)!)
    print(highestNumbers)
}

Shown again in playground

来源：https://stackoverflow.com/questions/36960520/how-can-i-find-the-highest-elements-of-an-array-in-swift