Here, We see Swift LinkedIn Skill Assessment Answer. This assessment test consists of 15-20 MCQs to demonstrate your knowledge of your selected skills. MCQs come from different topics – Classes and Structs, Closures and Functions, Control Flow, General, and Types..
List of all LinkedIn Skills Assessment Answer
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Swift LinkedIn Skill Assessment Answer
Q1. What is this code an example of?
let val = (Double)6
Code language: JavaScript (javascript)
- A syntax issue✔
- Typecasting
- Assignment
- Initialization
Reference: The Swift Programming Language: Language Guide: The Basics: Constants and Variables
Q2. What is the error in this code?
let x =5guard x ==5 { return }
Code language: JavaScript (javascript)
- The guard is missing the else✔
- Nothing is wrong
- The
guard
is missing athen
- The comparison is wrong
Reference: The Swift Programming Language: Language Guide: Control Flow: Early Exit
Q3. What is the raw/underlying type of this enum?
enumDirection {
case north, south, east, west
}
Code language: JavaScript (javascript)
- There is none✔
-
String
-
Any
-
Int
Reference: The Swift Programming Language: Language Guide: Enumerations: Raw Values
Q4. Why is dispatchGroup used in certain situations?
- It allows multiple synchronous or asynchronous operations to run on different queues.
- It allows tracking and control execution of multiple operations together.
- It allows operations to wait for each other as desired.
- All of these answers.✔
Reference: Apple Developer: Documentation: Dispatch: Dispatch Group
Q5. What is this code an example of?
let val =5print("value is: \(val)")
Code language: JavaScript (javascript)
- String interpolation✔
- String compilation
- Method chaining
- String concatenation
Reference: The Swift Programming Language: Language Guide: Strings and Characters: String Interpolation
Q6. What are the contents of vals after this code is executed?
var vals = [10, 2]
vals.sort { (s1, s2) -> Boolin
s1 > s2
}
Code language: JavaScript (javascript)
- [10, 2]✔
- [2, 10]
- nil
- This code contains an error
Reference: Apple Developer: Documentations: Swift: Array: sort()
Q7. What does this code print?
typealiasThing= [String: Any]
var stuff: Thingprint(type(of: stuff))
Code language: JavaScript (javascript)
- Dictionary<String, Any>✔
- Dictionary
- Error
- Thing
Reference: The Swift Programming Language: Language Reference: Types: Type Identifier
Q8. What is the value of y?
let x = ["1", "2"].dropFirst()
let y = x[0]
Code language: JavaScript (javascript)
- This code contains an error✔
- 1
- 2
- nil
Q9. What is the value of the test in this code?
var test =1==1
Code language: JavaScript (javascript)
- true✔
- YES
- 1
- This code contains an error
Reference: The Swift Programming Language: Language Guide: Basic Operators: Comparison Operators
Q10. What is the value of y?
var x: Int?
let y = x ??5
Code language: JavaScript (javascript)
- 5✔
- 0
- nil
- This code contains an error
Reference: The Swift Programming Language: Language Guide: Basic Operators: Nil-Coalescing Operators
Q11. What is the type of this function?
funcadd(a: Int, b: Int) -> Int { return a+b }
Code language: JavaScript (javascript)
- Int
- (Int, Int) -> Int✔
- Int<Optional>
- Functions don’t have types.
Reference: The Swift Programming Language: Language Guide: Functions: Function Types
Q12. What is the correct way to call this function?
funcmyFunc(_a: Int, b: Int) -> Int {
return a + b
}
Code language: JavaScript (javascript)
- myFunc(5, b: 6)✔
- myFunc(5, 6)
- myFunc(a: 5, b: 6)
- myFunc(a, b)
Q13. The Codable protocol is _?
- A combination of Encodable and Decodable✔
- Not a true protocol
- Required of all classes
- Automatically included in all classes
References:
- Apple Developer: Documentation: Swift: Swift Standard Library: Encoding, Decoding, and Serialization: Codable
- The Swift Programming Language: Language Guide: Protocols: Protocol Composition
Q14. What is the type of value1 in this code?
let value1 ="\("test".count)"
Code language: JavaScript (javascript)
- String✔
- Int
- null
- test.count
Reference: The Swift Programming Language: Language Guide: Strings and Characters: String Interpolation
Q15. When a function takes a closure as a parameter, when do you want to mark it as escaping?
- When it’s executed after the function returns✔
- When it’s scope is undefined
- When it’s lazy-loaded
- All of these answers
Reference: The Swift Programming Language: Language Guide: Closures: Escaping Closures
Q16. What’s wrong with this code?
classPerson {
var name: Stringvar address: String
}
Code language: JavaScript (javascript)
- A person has no initializers.✔
- A person has no base class.
-
var name
is not formatted correctly. -
address
is a keyword.
Reference: The Swift Programming Language: Language Guide: Initialization: Class Inheritance and Initialization
Q17. What is the value of names after this code is executed?
let names = ["Bear", "Joe", "Clark"]
names.map { (s) -> Stringinreturn s.uppercased()
}
Code language: JavaScript (javascript)
- [“BEAR”, “JOE”, “CLARK”]
- [“B”, “J”, “C”]
- [“Bear”, “Joe”, “Clark”]✔
- This code contains an error.
Q18. What describes this line of code?
let val =5
Code language: JavaScript (javascript)
- A constant named val of type Int✔
- A variable named val of type item
- A constant named val of type Number
- A variable named val of type Int
Reference: The Swift Programming Language: Language Guide: The Basics: Type Safety and Type Inference
Q19. What is the error in this code?
extensionString {
var firstLetter: Character="c" {
didSet {
print("new value")
}
}
}
Code language: PHP (php)
- Extensions can’t add properties.✔
- Nothing is wrong with it.
-
didSet
takes a parameter. -
c
is not a character.
Reference: The Swift Programming Language: Language Guide: Extensions: Computed Properties
Q20. didSet and willSet are examples of _?
- Property observers✔
- Key properties
- All of these answers
-
newOld
value calls
Reference: The Swift Programming Language: Language Guide: Properties
Q21. What is wrong with this code?
self.callback = {
self.attempts +=1self.downloadFailed()
}
Code language: PHP (php)
- Use of self inside the closure causes the retain cycle.✔
- You cannot assign a value to a closure in this manner.
- You need to define the type of closure explicitly.
- There is nothing wrong with this code.
Q22. How many values do vals have after this code is executed?
var vals =Set<String> = ["4", "5", "6"]
vals.insert("5")
Code language: JavaScript (javascript)
- Three
- Four
- Eight
- This code contains an error.✔
Reference: The Swift Programming Language: Language Guide: Collection Types: Sets
Q23. How can you avoid a strong reference cycle in a closure?
- Use a capture list to set class instances of weak or unowned.✔
- You can’t, there will always be a danger of strong reference cycles inside a closure.
- Initialize the closure as read-only.
- Declare the closure variable as
lazy
.
Reference: The Swift Programming Language: Language Guide: Automatic Reference Counting
Q24. What is wrong with this code?
iflet s =String.init("some string") {
print(s)
}
Code language: JavaScript (javascript)
- This String initializer does not return an optional.✔
- String does not have an initializer that can take a
String
. -
=
is not a comparison. - Nothing is wrong with this code.
Reference: The Swift Programming Language: Language Guide: The Basics: Optionals
Q25. Which code snippet correctly creates a type alias closure?
- typealias CustomClosure = () -> ()✔
- typealias CustomClosure { () -> () }
- typealias CustomClosure -> () -> ()
- typealias CustomClosure -> () {}
Reference: The Swift Programming Language: Language Reference: Declarations: Type Alias Declaration
Q26. How do you reference class members from within a class?
- self✔
- instance
- class
- this
Reference: The Swift Programming Language: Language Guide: Methods: Instance Methods
Q27. All value types in Swift are _ under the hood.
- Structs✔
- Classes
- Options
- Generics
Reference: The Swift Programming Language: Language Guide: Structures and Classes
Q28. What is the correct way to add a value to this array?
var strings = [1, 2, 3]
Code language: JavaScript (javascript)
- All of these answers✔
- strings.append(4)
- strings.insert(5, at: 1)
- strings += [5]
Reference: The Swift Programming Language: Language Guide: Collection Types: Arrays
Q29. How many times will this loop be executed?
for i in0...100 {
print(i)
}
Code language: PHP (php)
- 0
- 101✔
- 99
- 100
References:
- The Swift Programming Language: Language Guide: Control Flow: For-in Loops
- The Swift Programming Language: Language Guide: Basic Operators: Range Operators
Q30. What can AnyObject represent?
- An instance of any class✔
- An instance of function type
- All of these answers
- An instance of an optional type
Reference: The Swift Programming Language: Language Guide: Type Casting: Type Casting for Any and AnyObject
Q31. What is the value of t after this code is executed?
let names = ["Larry", "Sven", "Bear"]
let t = names.enumerated().first().offset
Code language: JavaScript (javascript)
- This code does not compile. / This code is invalid.✔
- 0
- 1
- Larry
References:
- Apple Developer: Documentation: Swift: Array: enumerated()
- Apple Developer: Documentation: Swift: Array
Q32. What is the value of the test after this code executes?
let vt = (name: "ABC", val: 5)
let test = vt.0
Code language: JavaScript (javascript)
- ABC✔
- 0
- 5
- name
References:
- The Swift Programming Language: Language Guide: The Basics: Tuples
- The Swift Programming Language: Language Reference: Expressions: Primary Expressions: Tuple Expression
Q33. What is the base class in this code?
classLSN: MMM {
}
Code language: CSS (css)
- MMM✔
- LSN
- There is no base class.
- This code is invalid.
Reference: The Swift Programming Language: Language Guide: Inheritance: Subclassing
Q34. What does this code print to the console?
var userLocation: String="Home" {
willSet(newValue) {
print("About to set userLocation to \(newValue)...")
}
didSet {
if userLocation != oldValue {
print("userLocation updated with new value!")
} else {
print("userLocation already set to that value...")
}
}
}
userLocation ="Work"
Code language: PHP (php)
- About to set userLocation to Work… userLocation updated with new value!✔
- About to set userLocation to Work… userLocation already set to that value…
- About to set userLocation to Home… userLocation updated to new value!
- Error
Reference: The Swift Programming Language: Language Guide: Properties: Property Observers
Q35. What must a convenience initializer call?
- A base class convenience initializer
- Either a designated or another convenience initializer
- A designated initializer✔
- None of these answers
Reference: The Swift Programming Language: Language Guide: Initialization: Class Inheritance and Initialization
Q36. Which object allows you access to specify that a block of code runs in a background thread?
- DispatchQueue.visible
- DispatchQueue.global✔
- error example needs to be labeled as throws.
- DispatchQueue.background
Reference: Apple Developer: Documentation: Dispatch: DispatchQueue
Q37. What is the inferred type of x?
let x = ["a", "b", "c"]
Code language: JavaScript (javascript)
- String[]
- Array<String>✔
- Set<String>
- Array<Character>
Reference: The Swift Programming Language: Language Guide: Collection Types: Arrays
Q38. What is the value of things after this code is executed?
let nThings: [Any] = [1, "2", "three"]
let oThings = nThings.reduce("") { "\($0)\($1)" }
Code language: JavaScript (javascript)
- 11212three
- 115
- 12three✔
- Nothing, this code is invalid.
Reference: Apple Developer: Documentation: Swift: Array: reduce(_:_:)
Q39. How would you call a function that throws errors and also returns a value?
- !try
- try?✔
- try!
- ?try
Reference: The Swift Programming Language: Language Guide: Error Handling: Handling Errors
Q40. What is wrong with this code?
protocolTUI {
funcadd(x1: Int, x2: Int) -> Int {
return x1 + x2
}
}
Code language: JavaScript (javascript)
- Protocol functions cannot have return types.
- Protocol functions cannot have implementations.✔
- Nothing is wrong with it.
-
add
is a reserved keyword.
Reference:
- The Swift Programming Language: Language Guide: Protocols: Method Requirements
- The Swift Programming Language: Language Guide: Protocols: Protocol Extensions
Q41. In this code, what are wheels and doors examples of?
classCar {
var wheels: Int=4let doors =4
}
Code language: JavaScript (javascript)
- Class members
- This code is invalid
- Class fields
- Class properties✔
Reference:
- The Swift Programming Language: Language Guide: Structures and Classes
- The Swift Programming Language: Language Guide
Q42. How do you designate a failable initializer?
- You cannot
- deinit
- init?✔
- init
Reference:
- The Swift Programming Language: Language Guide: Initialization
- The Swift Programming Language: Language Guide: Deinitialization
Q43. What is printed when this code is executed?
let dbl =Double.init("5a")
print(dbl ??".asString()")
Code language: JavaScript (javascript)
- five
- 5a
- .asString()✔
- 5
Reference:
- The Swift Programming Language: Language Guide: Basic Operators: Nil-Coalescing Operator
- The Swift Programming Language: Language Guide: Initialization: Failable Initializers
Q44. In the function below, what are these and toThat examples of?
funcadd(thisx: Int, toThaty: Int) { }
Code language: CSS (css)
- None of these answers
- Local terms
- Argument labels✔
- Parameters names
Reference: The Swift Programming Language: Language Guide: Functions
Q45. What is wrong with this code?
for (key, value) in [1: "one", 2: "two"] {
print(key, value)
}
Code language: PHP (php)
- The interaction source is invalid
- The interaction variable is invalid
- There is nothing wrong with this code✔
- The comma in the print is misplaced
Reference: The Swift Programming Language: Language Guide: Control Flow: For-In Loops
Q46. Which of these choices is associated with unit testing?
-
XCTest
- All of these answers✔
-
@testable
-
XCTAssert
Reference:
- Apple Developer: Documentation: XCTest: XCTest
- Apple Developer: Documentation: XCTest: Boolean Assertions: XCTAssert(_:_:file:line:)
- The Swift Programming Language: Language Guide: Access Control: Access Levels
Q47. In the code below, what is width an example of?
classSquare {
var height: Int=0var width: Int {
return height
}
}
Code language: JavaScript (javascript)
- This code contains an error
- A closure
- A computed property✔
- Lazy loading
Reference:
- The Swift Programming Language: Language Guide: Properties: Stored Properties
- The Swift Programming Language: Language Guide: Properties: Computed Properties
- The Swift Programming Language: Language Guide: Closures: Trailing Closures
Q48. What data type is this an example of?
let vals = ("val", 1)
Code language: JavaScript (javascript)
- A dictionary
- A tuple✔
- An optional
- This code contains an error
Reference:
- The Swift Programming Language: Language Guide: The Basics
- The Swift Programming Language: Language Reference: Types
Q49. What is wrong with this code?
var x =5
x =10.0
Code language: JavaScript (javascript)
- You cannot assign a Double to a variable of type Int✔
-
x
is undefined -
x
is a constant -
x
has no type
Reference: The Swift Programming Language: Language Guide: The Basics
Q50. What will this code print to the console?
var items = ["a": 1, "b": 2, "c": "test"] as [String: Any]
items["c"] =nilprint(items["c"] asAny)
Code language: JavaScript (javascript)
- Any
- test
- 1,2,3
- nil✔
References:
- The Swift Programming Language: Language Guide: Type Casting: Type Casting for Any and AnyObject
- The Swift Programming Language: Language Guide: Collection Types: Dictionaries
Q51. What is wrong with this code?
let val =5.0+10
Code language: JavaScript (javascript)
- There is nothing wrong with this code✔
-
val
is a constant and cannot be changed -
5.0
and10
are different types - There is no semicolon
Reference: The Swift Programming Language: Language Guide: The Basics: Type Safety and Type Inference
Q52. How many parameters does the initializer for the Test have?
structTest {
var score: Intvar date: Date
}
Code language: JavaScript (javascript)
- Zero
- This code contains an error
- Two✔
- Structs do not have initializers
Reference: The Swift Programming Language: Language Guide: Initialization
Q53. What prints to the console when executing this code?
let x =try?String.init("test")
print(x)
Code language: JavaScript (javascript)
- nil
- Nothing – this code contains an error
- Optional(“test”)✔
- test
References:
- The Swift Programming Language: Language Guide: Error Handling: Handling Errors
- The Swift Programming Language: Language Guide: The Basics: Optionals
Q54. How can you sort this array?
var vals = [1, 2, 3]
Code language: JavaScript (javascript)
-
vals.sort { $0 < $1 }
-
vals.sort { (s1, s2) in s1 < s2 }
-
vals.sort(by: <)
- All of these answers✔
Reference: Apple Developer: Documentation: Swift: Array: sort()
Q55. DispatchQueue.main.async takes a block that will be
- Not executed
- Executed in the main queue✔
- None of these answers
- Executed on the background thread
Reference: Apple Developer: Documentation: Dispatch: DispatchQueue: async(group:qos:flags:execute:)
Q56. When is deinit called?
- When a class instance needs memory
- All of these answers
- When the executable code is finished
- When a class instance is being removed from memory✔
Reference: The Swift Programming Language: Language Guide: Deinitialization
Q57. How do you declare an optional String?
- String?✔
- Optional[String]
- [String]?
- ?String
Reference: The Swift Programming Language: Language Guide: The Basics: Optionals
Q58. How many times this code will be executed? / How many times will this loop be performed?
for i in ["0", "1"] {
print(i)
}
Code language: PHP (php)
- One
- Two✔
- Three
- This code does not compile
Reference: The Swift Programming Language: Language Guide: Control Flow: For-In Loops
Q59. What does this code print?
let names = ["Bear", "Tony", "Svante"]
print(names[1] +"Bear")
Code language: JavaScript (javascript)
- 1Bear
- BearBear
- TonyBear✔
- Nothing, this code is invalid
References:
- The Swift Programming Language: Language Guide: Collection Types: Arrays
- The Swift Programming Language: Language Guide: Strings and Characters: Concatenating Strings and Characters
Q60. What is true of this code?
let name: String?
Code language: JavaScript (javascript)
- name can hold only a string value.
- name can hold either a string or nil value.✔
- Optional values cannot be
let
constants. - Only non-empty string variables can be stored in the name.
Reference: The Swift Programming Language: Language Guide: The Basics: Optionals
Q61. What is the value of val after this code is executed?
let i =5let val = i *6.0
Code language: JavaScript (javascript)
- This code is invalid.✔
- 6
- 30
- 0
Reference: The Swift Programming Language: Language Guide: The Basics: Type Safety and Type Inference
Q62. What does this code print?
enumPositions: Int {
case first, second, third, other
}
print (Positions.other.rawValue)
Code language: PHP (php)
- 3✔
- 0
- other
- nil
Reference: The Swift Programming Language: Language Guide: The Basics: Raw Values
Q63. What is printed to the console when this code is executed?
"t".forEach { (char) inprint(char)
}
Code language: PHP (php)
- nil
- Nothing, since the code contains an error
- t✔
- zero
References:
- The Swift Programming Language: Language Guide: Strings and Characters: Working with Characters
- Apple Developer: Documentation: Swift: String: forEach(_:)
Q64. What prints when this code is executed?
let s1 = ["1", "2", "3"]
.filter { $0>"0" }
.sorted { $0>$1 }
print(s1)
Code language: JavaScript (javascript)
- []
- [“3”, “2”, “1”]✔
- [321]
- [“1”, “2”, “3”]
References:
- Apple Developer: Documentation: Swift: Swift Standard Library: Collections: Sequence and Collection Protocols: Sequence: filter()
- Apple Developer: Documentation: Swift: Array: sorted()
Q65. What enumeration feature allows them to store case-specific data?
- Associated values✔
- Integral values
- Raw values
- Custom values
Reference: The Swift Programming Language: Language Guide: Enumerations: Associated Values
Q66. In the code below, AOM must be a(n)?
classAmP: MMM, AOM { }
Code language: CSS (css)
- Class
- Protocol✔
- Enumeration
- Struct
References:
- The Swift Programming Language: Language Guide: Inheritance: Subclassing
- The Swift Programming Language: Language Guide: Protocols: Protocol Syntax
Q67. What is the value of numbers in the code below?
let numbers = [1, 2, 3, 4, 5, 6].filter { $0%2==0 }
Code language: JavaScript (javascript)
- [1, 3, 5]
- []
- [2, 4, 6]✔
- nil
Q68. What is the type of vals in this code?
let vals = ["a", 1, "Hi"]
Code language: JavaScript (javascript)
- Array(char)
- [Any]✔
- Array
- [Generic]
Reference: The Swift Programming Language: Language Guide: Type Casting
Q69. How can you extract value to x in tuple vt
let vt = (name: "ABC", val: 5)
Code language: JavaScript (javascript)
- let x = vt.1
- All of these answers✔
- let x = vt.val
- let (
_
, x) = vt
Reference: The Swift Programming Language: Language Guide: The Basics: Tuples
Q70. What is the type of x?
let x =try?String.init(from: decoder)
Code language: JavaScript (javascript)
- String
- String?✔
- String!
- try?
Reference: The Swift Programming Language: Language Guide: Error Handling: Handling Errors
Q71. How many times is this loop executed?
let loopx =5repeat {
print (loopx)
} while loopx <6
Code language: JavaScript (javascript)
- Six
- Zero
- Five
- Infinite✔
Reference: The Swift Programming Language: Language Guide: Control Flow: While Loops
Q72. How many values do vals have after this code is executed?
var vals: Set<String> = ["4", "5", "6"]
vals.insert("5")
Code language: JavaScript (javascript)
- This code contains an error.
- Eight
- Three✔
- Four
Reference: The Swift Programming Language: Language Guide: Collection Types: Sets
Q73. What is the base class in this code?
class LSN: MMM{ }
Code language: CSS (css)
- MMM✔
- LSN
- There is no base class.
- This code is invalid.