loop.swift

//: Playground - noun: a place where people can play

import UIKit

enum PersonalAccount {
    case credit(amount: Int64, id: UInt)
    case debit(amount: UInt64, id: UInt)
}

let accounts: [PersonalAccount] = [.credit(amount: -1000, id: 1),
                                   .debit(amount: 1000, id:2),
                                   .credit(amount: -1000000, id: 3)]

// MARK: Regular construction
for account in accounts {
    if case let .credit(amount, id) = account {
        print("amount: \(amount) id: \(id)")
    }
}

// MARK: Using pattern matching
for case let .credit(amount, id) in accounts {
    print("amount: \(amount) id: \(id)")
}

/*
 amount: -1000 id: 1
 amount: -1000000 id: 3
 */

// MARK: One more example using 'where' keyword
let views: [UIView] = [UIButton(), UILabel(), UIScrollView(), UILabel()]

for view in views where view is UILabel {
    print("view class: \(view.self)")
}