Ternary Conditional Operator, Nil-Coalescing Operator

Swift Programming Language Guide: Basic Operators. 코드부분

/* Ternary Conditional Operator */

// The ternary conditonal operator is a special operator with three parts, which takses the form question ? answer 1 : answer2.

if question {

    answer1

} else {

    answer2

}

let contentHeight = 40

let hasHeader = true

let rowHeight = contentHeight + (hasHeader ? 50 : 20)

let contentHeigth = 40

let hasHeader = true

let rowHeight: Int

if hasHeader {

    rowHeight = contentHeigth + 50

} else {

    rowHeight = contentHeigth + 20

}

/* Nil-Coalescing Operator */

//The nil-coalescing operator (a ?? b) unwraps an optional a if it contains a value, or returns a default value b if a is nil.

a != nil ? a! : b

let defaultColorName = "red"

var userDefinedColorName: String?

var colorNameToUse = userDefinedColorName ?? defaultColorName

userDefinedColorName = "green"

colorNameToUse = userDefinedColorName ?? defaultColorName