Swift: For case let example

forcaselet.swift

import Foundation

enum State {
    case idle
    case running(speed: Double)
    case paused(duration: TimeInterval)
    case stopped(reason: String)
}

let states: [State] = [.idle, .paused(duration: 2), .running(speed: 10), .running(speed: 2)]

for case let .running(speed) in states {
    print(speed)
}