Functions

Global Functions
the functions print, min, and abs are a few examples of global functions.

print("I'm a global function!", terminator:"")

var initialPrice = 50
var bestOffer = 45
var finalPrice = min(bestOffer, initialPrice)

var negativeSeven = -7
abs(negativeSeven)

Anatomy of a function

let array = ["A", "13", "B", "5", "87", "t", "41"]

class Arithmetic {
	func sumOfStrings(aBunchOfStrings: [String]) -> Int {
		let array = aBunchOfStrings
		var sum = 0
		for string in array {
			if Int(string) != nil {
				let intToAdd = Int(string)!
				sum += intToAdd
			}
		}
		return sum
	}
}

func functionName (parameterName: parameterType) -> returnType
statements to execute
return object
}

let stringToReverse = "Mutable or Immutable? That is the question."

func reverseString(stringToReverse: String){
	var reversedString = ""
	for character in stringToReverse.characters {
		reversedString = "\(character)" + reversedString
	}
	print(reversedString)
}

func functionName(externalParamName localParamName: paramType) -> returnType {
statements to execute
return object
}

func firstCharaterOf(word: String) -> Character {
	return word[word.startIndex]
}

firstCharacterOf("Mom")

func placeFirstLetterLast(var myString: String) -> String {
	myString.append(firstCharacterOf(word: myString))
	myString.removeAtIndex(myString.startIndex)
	return "placeholder"
}

placeFirstLetterLast("Mom")

class MovieArchive {
	func filterByYear(year: Int, movies: Dictionary<String, Int> -> [String]{
		var filteredArray = [String]()
		for (movie, releaseYear) in movies {
			if year == releaseYear{
				filteredArray.append(movie)
			}
		}
		return filteredArray
	})
}

var aiThemedMovies = ["Metropolis":1927, "2001:A Space Odessey":1968, "Blade Runner":1982, "War Games":1983, "Terminator":1984, "The Matrix":1999, "A.I.":2001, "Her":2013, "Ex Machina":2015]

var myArchive = MovieArchive()
myArchive.filterByYear(2013, movies: aiThemedMovies)