How to reverse array in Swift without using ".reverse()"?

Here is how I did it and there is no warning for Swift 3

let names = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]
var reversedNames = [String]()

for name in names.enumerate() {
let newIndex = names.count - 1 - name.index
reversedNames.append(names[newIndex])
}

or just simply

reversedNames = names.reverse()

Only need to make (names.count/2) passes through the array. No need to declare temporary variable, when doing the swap...it's implicit.

var names:[String] = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]
let count = names.count
for i in 0..<count/2 {
(names[i],names[count - i - 1]) = (names[count - i - 1],names[i])
}
// Yields: ["Asus", "Lenovo", "Sony", "Microsoft", "Apple"]

This will work with any sized array.

import Cocoa

var names:[String] = [ "A", "B", "C", "D", "E","F"]
var c = names.count - 1
for i in 0...(c/2-1) { swap(&names[i],&names[c-i]) }

print(names)

There's also `stride` to generate a reversed index:

let names = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]

var reversed = [String]()

for index in (names.count - 1).stride(to: -1, by: -1) {
reversed.append(names[index])
}

It also works well with `map`:

let reversed = (names.count - 1).stride(to: -1, by: -1).map { names[$0] }

*Note: `stride` starts its index at 1, not at 0, contrary to other Swift sequences.*

However, to anyone reading this in the future: **use `.reverse()`** instead to actually reverse an array, it's the intended way.

Here you go:

var names:[String] = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]

var reversedNames = [String]()

for var arrayIndex = names.count - 1 ; arrayIndex >= 0 ; arrayIndex-- {
reversedNames.append(names[arrayIndex])
}

Like this, maybe:

names = names.enumerate().map() { ($0.index, $0.element) }.sort() { $0.0 > $1.0 }.map() { $0.1 }

Oh, wait.. I *have* to use `for` loop, right? Then like this probably:

for (index, name) in names.enumerate().map({($0.index, $0.element)}).sort({$0.0 > $1.0}).map({$0.1}).enumerate() {
names[index] = name
}