Using stride() to loop over a range of numbers

Swift version: 5.1

Paul Hudson    @twostraws    May 28th 2019

Swift has a helpful stride(), which lets you move from one value to another using any increment – and even lets you specify whether the upper bound is exclusive or inclusive.

First, some examples. This first example counts from 0 to 10 in 2s:

for i in stride(from: 0, to: 10, by: 2) {
    print(i)
}

This second example counts from 0.1 up to to 0.5, exclusive:

for i in stride(from: 0, to: 0.5, by: 0.1) {
    print(i)
}

Both those examples use stride(from:to:by:), which counts from the start point up to by excluding the to parameter. If you want to count up and including the to parameter, you should use stride(from:through:by:), like this:

for i in stride(from: 0, through: 10, by: 2) {
    print(i)
}

Available from iOS 7.0

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