Swift’s standard library offers several different APIs for extracting a range of elements from any sequence. For example, we can use dropFirst and dropLast to remove the first or last element — or use prefix and suffix to extract a subsequence with a given amount of leading or trailing elements.

// Since the first argument passed to a command line
// tool is the execution path, we drop it to have the
// first element become the first user-passed argument:
let arguments = CommandLine.arguments.dropFirst()

// Calling 'prefix' or 'suffix' on a sequence lets us
// extract a subsequence containing up to a certain
// number of elements, without crashing if the sequence
// doesn't contain enough elements:
let intro = text.split(separator: " ").prefix(10)
let outro = text.split(separator: " ").suffix(10)

// The above operations are optimized to not cause
// unnecessary copying, so if we want to turn the
// results into a new array, we must do so explicitly:
let words = Array(intro)

For two weeks, many websites around the Swift community are featuring indie developers who have been financially impacted by the current pandemic. If you can, please help support these indies by downloading their apps. Today’s app is...

HazeOver: Minimize distractions by automatically dimming all Mac windows except the currently active one. Perfect for when you want to maintain focus on a task, without having to go full screen.