Swift Syntax

Question 1

for-in loop

Answer 1

for  in  {
// code to be executed
}

Question 2

if statement

Answer 2

var Christmas = true
if Christmas { print("A Savior has been born!") }

Question 3

function

Answer 3

func  (: ,
                                       : , ... ) ->  {
// Function code
}

Question 4

calling a function with specified parameter/data type

Answer 4

funcName(paramName:paramArgument)

Question 5

while loop

Answer 5

while condition {
  // Execute while condition remains true
}

example
while total < 50 {
  let diceRoll = Int.random(in: 1...6)
  total += diceRoll
}

Question 6

for-in loops

Answer 6

used to iterate over collection items like ranges and strings.

Question 7

stride( )

Answer 7

creates a range that we can customize.

Question 8

Create an empty dictionary using dictionary literal syntax

Answer 8

var dictionaryName: [KeyType: ValueType] = [:]

Question 9

create an empty dictionary using initializer syntax

Answer 9

var dictionaryName = KeyType: ValueType

Question 10

create a populated dictionary

Answer 10

var dictionaryName: [KeyType: ValueType] = [
  Key1: Value1,
  Key2: Value2,
  Key3: Value3
]

Question 11

create a dictionary with type inference

Answer 11

var fruitStand = [
“Apples”: 12,
“Bananas”: 20
]

Question 12

add new key-value to dictionary (or update existing)

Answer 12

dictionaryName[NewKey] = NewValue

Question 13

update dictionary value using updateValue() method

Answer 13

dictionaryName.updateValue(“NewValueName”, forKey: “KeyName”)

Question 14

remove key-value pair from dictionary using nil

Answer 14

dictionaryName[“keyName”] = nil

Question 15

remove key-value pair from dictionary using .removeValue( ) method

Answer 15

dictionaryName.removeValue(forKey:”keyName”)

Question 16

remove all elements from a dictionary

Answer 16

dictionaryName.removeAll( )

Question 17

determine if a dictionary is empty

Answer 17

dictionaryName.isEmpty

Question 18

determine the number of elements contained in a dictionary

Answer 18

dictionaryName.count

Question 19

extract a value from dictionary and assign it to a new variable

Answer 19

var newVariable = dictionaryName[“keyName”]

Question 20

if-let statement

Answer 20

if let newVarName = dictionaryName["keyName"] {
action to perform
}

Question 21

iterate through a dictionary

Answer 21

for (keyHolder, valueHolder) in dictionaryName {
  // Body of loop
}

Question 22

The syntax for creating an instance

Answer 22

var ferris = Student()

Question 23

Syntax for init() method

Answer 23

class className {
  var property = value
  init (property: valueType) {
     self.property = property
  }
}

Question 24

Syntax to create a subclass that inherits from a superclass

Answer 24

class Subclass: Superclass {
}

Question 25

Create subclass to inherit from super class with new property with default value of 2.0

Answer 25

``` class SubClass: SuperClass { var newProperty = 2.0 } ```

Question 26

closed range operator

Answer 26

x...y // Starts at x and ends at y

Question 27

half-open range operator

Answer 27

x..

Question 28

One-sided range operator

Answer 28

x... /* or */ ...y // specifies a range that can extend as far as possible in a specified range direction until the natural beginning or end of the range is reached, can be used w/strings.

Question 29

The Ternary Operator

Answer 29

condition ? true expression : false expression

Question 30

Nil Coalescing Operator

Answer 30

``` let customerName: String? = nil print("Welcome back, \(customerName ?? "customer")") //The above example will output text which reads "Welcome back, customer" because the customerName optional is set to nil. ```

Question 31

repeat ... while loop

Answer 31

``` repeat { // Swift statements here } while EX. var i = 10 repeat { i -= 1 } while (i > 0) //In the repeat .. while example above the loop will continue until the value of a variable named i equals 0 ```

Question 32

"break" statement

Answer 32

``` var j = 10 for _ in 0 ..<100 { j += j if j > 100 { break } print ("j = \ (j) ") } ```

Question 33

"continue" statement

Answer 33

``` var i = 1 while i < 20 { i += 1 if ( i % 2 ) != 0 { continue } print ( " i = \ ( i ) " ) } // The "continue" statement in the above example will cause the print call to be skipped unless the value of "i" is even. // I.E. The print call will be skipped unless the condition is met ```

Question 34

if ... else if ...

Answer 34

``` if let x = 9 if x == 10 { print ( " x is 10 " ) } else if x == 9 { print ( " x is 9 " ) } else if x == 8 { print ( " x is 8 " ) } ```

Question 35

guard statement

Answer 35

``` guard ese { // code to be executed if expression is false ``` ``` } // code here is executed if expression is true ```

Question 36

switch statement

Answer 36

``` switch expression { case match1: statements case match2: statements case match3, match4: statements default: statements } ```

Question 37

Function with default function parameter

Answer 37

``` func buildMessageFor(_ name: String = "Customer, count: Int ) -> String } return ( "\(name), you are customer number \ (count) " ) } ```

Question 38

Function that returns multiple result values

Answer 38

``` func sizeConverter (_ length: Float ) -> (yards: Float, centimeters: Float, meters: Float) { let yards = length * 0.0277778 let centimeters = length * 2.54 let meters = length * 0.0254 ``` return (yards, centimeters, meters) }

Question 39

closure expression

Answer 39

``` The following code declares a closure expression and assigns it to a constant named sayHello and then calls the function via the constant reference EX: let sayHello = { print( "Hello" ) } sayHello( ) ```

Question 40

closure expression configured to accept parameters and return results

Answer 40

``` { ( : , , ... ) -> < return type> in // Closure expression code here } ```

Question 41

An array may be initialized with a collection of values (referred to as an array literal) at creation time using the following syntax

Answer 41

var variableName: [type] = [value 1, value2, value3, ..........]

Question 42

The following syntax can be used to create an empty array

Answer 42

var variableName = [type] ( )

Question 43

Array initialized to a specific size with each array element pre-set with a specified default value

Answer 43

var nameArray = [String] (repeating: "My String", count: 10)

Question 44

Syntax to create a new array by adding together two existing arrays

Answer 44

let thirdArray = firstArray + secondArray

Question 45

forEach( ) array method

Answer 45

arrName.forEach { element in print(element) }

Question 46

A new dictionary may be initialized with a collection of values (referred to as a dictionary literal) at creation time using the following syntax

Answer 46

var variableName: [key type: value type] = [key 1: value 1, key 2, value2 .... ]

Question 47

Syntax to create an empty dictionary

Answer 47

var variableName = [key type: value type]( )

Question 48

The following code creates an empty dictionary designated to store integer keys and string values

Answer 48

var myDictionary = [Int: String] ( )

Question 49

The following code iterates through all the entries in a dictionary, outputting both the key and value for each entry

Answer 49

for (keyName, valueName) in arrayName { print ("Key Name: \(keyName), valueName: \(valueName)") }