Beginner Swift

Question 1

Property of an array that counts the number of items in a given array.

Answer 1

Var.count

Question 2

What is an array?

Answer 2

A sequential list of variables. Always starts at 0, increments by one in order.

Var todo[string] = [“call”,”suck”]

To add a value on end:

todo += [“swallow”]

Question 3

A single operator that can affect the resulting value of a variable.

Answer 3

Unary operators

++ increment
– decrement
- negative
! Means variable or constant is negated

Question 4

Example of a function with a return type String..

Answer 4

func heyName(name: String) -> String {
     var greeting = "Hello \(name)"
     return greeting
}

Question 5

Allows you to create a new type that groups several related values.

Answer 5

Enum.

enum Coin {
case Penny, Nickel, Dime, Quarter
}

Penny etc are called “Members”

Question 6

What is a Switch statement?

Answer 6

A switch statement considers a value and compares it against several possible matching patterns. It then executes an appropriate block of code, based on the first successful match.
switch somevalue {
     case value 1:
          respond to value 1
     case value 2, value 3:
          respond to value 2 or 3
     default:
          otherwise do this 
}

Question 7

Adds an element to an array.

Can also update a car in middle of array.

Answer 7

Var.append( )

Question 8

Property of an array that counts the number of items in a given array.

Answer 8

Var.count

Question 9

What is an array?

Answer 9

A sequential list of variables. Always starts at 0, increments by one in order.

Var todo[string] = [“call”,”suck”]

To add a value on end:

todo += [“swallow”]

Question 10

A single operator that can affect the resulting value of a variable.

Answer 10

Unary operators

++ increment
– decrement
- negative
! Means variable or constant is negated

Question 11

Example of a function with a return type String..

Answer 11

func heyName(name: String) -> String {
     var greeting = "Hello \(name)"
     return greeting
}

Question 12

Allows you to create a new type that groups several related values.

Answer 12

Enum.

enum Coin {
case Penny, Nickel, Dime, Quarter
}

Penny etc are called “Members”

Question 13

What is a Switch statement?

Answer 13

A switch statement considers a value and compares it against several possible matching patterns. It then executes an appropriate block of code, based on the first successful match.
switch somevalue {
     case value 1:
          respond to value 1
     case value 2, value 3:
          respond to value 2 or 3
     default:
          otherwise do this 
}

Question 14

Adds an element to an array.

Can also update a car in middle of array.

Answer 14

Var.append( )

Question 15

What is Concatenation? Provide an example.

Answer 15

Adding objects together:

var greeting = “Hello” + language

Question 16

What is a mutable string? Provide an example.

Answer 16

A string that can be modified:

var language = “Swift”

Question 17

What’s an immutable string? Provide an example:

Answer 17

A string that can’t be modified:

let language = “Swift”

Question 18

What is a Struct? Provide an example.

Answer 18

A Struct allows you to create a new data type with stored properties:

struct Car {
var doors : Int
var wheels: Int
}

Question 19

Create an instance of the struct Car

Hint–make a sedan.

Answer 19

var sedan = Car(doors:4, wheels:4)

Question 20

When do you use an optional?

Answer 20

You use optional a in situations where a value may not be present. An optional says:

1) there IS a value, and it equals x, or
2) there ISNT a value at all (nil)

Question 21

How do you make an optional?

Answer 21

Adding ? To a type makes it an optional.

Question 22

How can we unwrap an optional?

Answer 22

The bang ! Operator unwraps an optional, but using if let to unwrap even better.

–note, needs example