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)”)
}