Looping n times
for var i = 0; i < 10; i++ {
print(i)
}
// use this:
for i in 0..<10 {
print(i)
}
Looping n times in reverse
for var i = 10; i > 0; i-- {
print(i)
}
// use this
for i in (1...10).reverse() {
print(i)
}
Looping with Stride
for var i = 0; i < 10; i += 2 {
print(i)
}
// use this
for i in 0.stride(to: 10, by: 2) {
print(i)
}
Looping through Array Values
let someNumbers = [2, 3, 45, 6, 8, 83, 100]
// instead of this
for var i = 0; i < someNumbers.count; i++ {
print(someNumbers[i])
}
// use this
for number in someNumbers {
print(number)
}
// or this
someNumbers.forEach { number in
print(number)
}
Reverse Looping through Array Values
let someNumbers = [2, 3, 45, 6, 8, 83, 100]
/* 100, 83, 8, 6, 45, 3, 2 */
// instead of this
for var i = someNumbers.count - 1; i >= 0; i-- {
print(someNumbers[i])
}
// use this
for number in someNumbers.reverse() {
print(number)
}
Looping Through an Array with Index
let someNumbers = [2, 3, 45, 6, 8, 83, 100]
/*
1: 2
2: 3
3: 45
4: 6
5: 8
6: 83
7: 100
*/
// instead of this
for var i = 0; i < someNumbers.count; i++ {
print("\(i + 1): \(someNumbers[i])")
}
// use this
for (index, number) in someNumbers.enumerate() {
print("\(index + 1): \(number)")
}
// or this
someNumbers.enumerate().forEach { (index, number) in
print("\(index + 1): \(number)")
}
Looping Through Array Indices
let someNumbers = [2, 3, 45, 6, 8, 83, 100]
/* 0, 1, 2, 3, 4, 5, 6 */
// instead of this
for var i = 0; i < someNumbers.count; i++ {
print(i)
}
// use this
for index in someNumbers.indices {
print(index)
}
from: Natasha the Robot
