Hands-On Design Patterns with Swift

Iterating, mapping, and reducing

Starting with Swift 3, C-style statements that are usually used when iterating through arrays have been removed, so you can no longer write the following:

for var i = 0; i < otherDoubles.count; i++  {    let element = otherDoubles[i]}

Instead, we use more powerful syntax:

A simple iterator is as follows:

for value in doubles  {    print("\(value)") // 1.0, 2.0, 3.0}

You can use an enumerator as follows:

for (idx, value) in doubles.enumerated()  {    print("\(idx) -> \(value)") // 0 -> 1.0, 1 -> 2.0, 2 -> 3.0}

Similarly, you can use the forEach method that will invoke a closure for each element, passing it as the first parameter:

doubles.forEach { value in    // do something with the value}

Next, we can transform the current ...