[Stanford Lecture] Swift and Foundation- Tuples, Range, Data Structure

 

# Tuples

What is a Tuple?

• 스위프트의 타입 중 하나
• 서로 다른 타입들을 그룹으로 묶어서 하나의 타입을 만든다.
• 타입이 들어갈 자리라면 어디든지 튜플을 사용할 수 있다.
  (You can use it anywhere you can use a type.)

 

 

 

 

# Range

• 무엇이든 연속적으로 표현할 수 있는 것의 양 끝 점을 가르킨다.
• Warning: A String subrange is not Range<Int> ( It is Range<String.Index> … we’ll talk later! )
• … 과 ..<

let array = ["a","b","c","d"]
let subarray1 = array[2...3]
let subarray2 = array[2..<3]
for i in 1...10 {
    print(i)
}

 

 

 

 

# Data  structures in Swift

 

Class, Struct, Enum

• 모두 프로퍼티와 함수를 가질 수 있음.
• 모두 같은 방법으로 선언: 키워드 + 이름 + {}
• Enum은 저장, 계산 프로퍼티를 가질 수 없음
• Enum은 초기화 함수 필요 없음 (연관값과 구별되는 값들에 할당을 해주었기 때문)
• Inheritance : Class 만 가능

 

# Value vs. Reference

Value (Struct and Enum)

• Copied when passed as an argument to a function
• Copied when assigned to a different variable
• 값 타입은 함수에서 인자로 전달될 때 복사하고, 다른 변수에 할당할 때도 복사
• Remember that function parameters  are constants
• You must note any func that can mutate a struct/enum with the keyword mutating
• Mutating func : 구조체의 값을 바꾸는 함수가 있는 구조체 함수 앞에 mutating을 붙여준다. (성능 향상을 위해)

 

Reference (Class)

• Stored in the heap and reference counted (automatically)
• 힙 메모리에 동일한 포인터 , 복사 X
• Constants pointers to a class (let) still can mutate by calling methods and changing properties
• let : 포인터가 변하지 않는다는 의미
• String, Double, Int, Array, Dictionary (Struct)
• Choosing which to use ?
• Usually you will choose class over struct. 
• Struct tends to be more for fundamental types.
• Use of enum is situational (any time you have a type of data with discrete values).
• 클래스보다는 더 작고 스스로 자립하며, 값으로 복사하는게 말이 되고, 값 타입을 원하는 영역들

 

 

 

	Class	Struct	Enum
Has property	O	O	O
has method	O	O	O
inheritance	O	X	X
pass by	ref	value	value
Init func	O	O	X