LinkedIn skill assessment answers and questions — Swift

“तीव्र has emerged as a powerful and intuitive programming language for developing iOS, मैक ओएस, and watchOS applications, offering developers a modern and efficient platform for building innovative software. इस व्यापक मार्गदर्शिका में, हम इसकी एक श्रृंखला प्रस्तुत करते हुए रोमांचित हैं skill assessment questions तथा जवाब के लिए विशेष रूप से तैयार किया गया तीव्र उपयोगकर्ताओं.

Whether you’re a seasoned developer looking to expand your capabilities or a beginner aiming to understand the basics of this powerful language, this resource is designed to help you become proficient in तीव्र और इसके अनुप्रयोग. Join us as we explore the core concepts of तीव्र प्रोग्रामिंग, including optionals, closures, protocols, और अधिक, empowering you to leverage the full potential of this essential tool for your iOS and macOS projects.”

Q1. What is this code an example of?

let val = (Double)6

A syntax issue
Typecasting
Assignment
Initialization

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Constants and Variables

Q2. What is the error in this code?

let x = 5
guard x == 5 { return }

NS guard is missing the else
Nothing is wrong
NS guard is missing a then
The comparison is wrong

संदर्भ: The Swift Programming Language: Language Guide: बहाव को काबू करें: Early Exit

Q3. What is the raw/underlying type of this enum?

enum Direction {
  case north, south, east, west
}

There is none
String
Any
Int

संदर्भ: 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 track and control execution of multiple operations together.
It allows operations to wait for each other as desired.
All of these answers.

संदर्भ: Apple Developer: प्रलेखन: Dispatch: Dispatch Group

Q5. What is this code an example of?

let val = 5
print("value is: \(val)")

String interpolation
String compilation
Method chaining
String concatenation

संदर्भ: 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) -> Bool in
  s1 > s2
}

[10, 2]
[2, 10]
nil
This code contains an error

संदर्भ: Apple Developer: Documentations: तीव्र: सरणी: क्रम से लगाना()

क्यू 7. What does this code print?

typealias Thing = [String: Any]
var stuff: Thing
print(type(of: stuff))

Dictionary<String, Any>
Dictionary
Error
Thing

संदर्भ: The Swift Programming Language: Language Reference: प्रकार: Type Identifier

क्यू 8. What is the value of y?

let x = ["1", "2"].dropFirst()
let y = x[0]

This code contains an error
1
2
nil

explanation
dropFirst() से Swift.Collection.Array returns a type of ArraySlice<Element>
as in the documentation pages:
@inlinable public func dropFirst(_ k: Int = 1) -> ArraySlice<Element>

The ArraySlice type makes it fast and efficient for you to perform operations on sections of a larger array. Instead of copying over the elements of a slice to new storage, an ArraySlice instance presents a view onto the storage of a larger array. And because ArraySlice presents the same interface as Array, you can generally perform the same operations on a slice as you could on the original array.

Slices Maintain Indices
Unlike Array and ContiguousArray, the starting index for an ArraySlice instance isn’t always zero. Slices maintain the same indices of the larger array for the same elements, so the starting index of a slice depends on how it was created, letting you perform index-based operations on either a full array or a slice.
The above code returns a slice of value ["2"] but the index did not change. let y = x[1] would give the expected result.
To safely reference the starting and ending indices of a slice, always use the startIndex and endIndex properties instead of specific values.
संदर्भ

प्रश्न 9. What is the value of test in this code?

var test = 1 == 1

true
YES
1
This code contains an error

संदर्भ: The Swift Programming Language: Language Guide: Basic Operators: Comparison Operators

प्र10. What is the value of y?

var x: Int?
let y = x ?? 5

5
0
nil
This code contains an error

संदर्भ: The Swift Programming Language: Language Guide: Basic Operators: Nil-Coalescing Operators

प्रश्न 11. What is the type of this function?

func add(a: Int, b: Int) -> Int { return a+b }

Int
(Int, Int) -> Int
Int<Optional>
Functions don’t have types.

संदर्भ: The Swift Programming Language: Language Guide: कार्यों: Function Types

प्र12. What is the correct way to call this function?

func myFunc(_ a: Int, b: Int) -> Int {
  return a + b
}

myFunc(5, b: 6)
myFunc(5, 6)
myFunc(a: 5, b: 6)
myFunc(a, b)

संदर्भ: The Swift Programming Language: Language Guide: कार्यों: Function Argument Labels and Parameter Names

प्रश्न 13. The Codable protocol is _?

A combination of Encodable तथा Decodable
Not a true protocol
Required of all classes
Automatically included in all classes

संदर्भ:

प्र14. What is the type of value1 in this code?

let value1 = "\("test".count)"

String
Int
null
test.count

संदर्भ: The Swift Programming Language: Language Guide: Strings and Characters: String Interpolation

प्रश्न 15. When a function takes a closure as a parameter, when do you want to mark is 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

संदर्भ: The Swift Programming Language: Language Guide: Closures: Escaping Closures

प्र16. What’s wrong with this code?

class Person {
  var name: String
  var address: String
}

Person has no initializers.
Person has no base class.
var name is not formatted correctly.
address is a keyword.

संदर्भ: The Swift Programming Language: Language Guide: Initialization: Class Inheritance and Initialization

प्रश्न 17. What is the value of names after this code is executed?

let names = ["Bear", "Joe", "Clark"]
names.map { (s) -> String in
  return s.uppercased()
}

["BEAR", "JOE", "CLARK"]
["B", "J", "C"]
["Bear", "Joe", "Clark"]
This code contains an error.

प्रश्न 18. What describes this line of code?

let val = 5

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

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Type Safety and Type Inference

क्यू19. What is the error in this code?

extension String {
  var firstLetter: Character = "c" {
    didSet {
      print("new value")
    }
  }
}

Extensions can’t add properties.
Nothing is wrong with it.
didSet takes a parameter.
c is not a character.

संदर्भ: The Swift Programming Language: Language Guide: Extensions: Computed Properties

प्र20. didSet and willSet are examples of _?

Property observers
Key properties
All of these answers
newOld value calls

संदर्भ: The Swift Programming Language: Language Guide: गुण

प्र21. What is wrong with this code?

self.callback = {
  self.attempts += 1
  self.downloadFailed()
}

Use of self inside the closure causes 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.

संदर्भ: The Swift Programming Language: Language Guide: Automatic Reference Counting: Strong Reference Cycles for Closures

प्र22. How many values does vals have after this code is executed?

var vals = Set<String> = ["4", "5", "6"]
vals.insert("5")

Three
चार
Eight
This code contains an error.

संदर्भ: The Swift Programming Language: Language Guide: Collection Types: सेट

प्र23. How can you avoid a strong reference cycle in a closure?

Use a capture list to set class instances of weak या 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.

संदर्भ: The Swift Programming Language: Language Guide: Automatic Reference Counting

प्र24. What is wrong with this code?

if let s = String.init("some string") {
  print(s)
}

इस 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.

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Optionals

प्रश्न25. Which code snippet correctly creates a typealias closure?

typealias CustomClosure = () -> ()
typealias CustomClosure { () -> () }
typealias CustomClosure -> () -> ()
typealias CustomClosure -> () {}

संदर्भ: The Swift Programming Language: Language Reference: Declarations: Type Alias Declaration

प्र26. How do you reference class members from within a class?

self
instance
class
this

संदर्भ: The Swift Programming Language: Language Guide: तरीकों: Instance Methods

प्र27. All value types in Swift are _ under the hood?

Structs
कक्षाओं
Optionals
Generics

संदर्भ: The Swift Programming Language: Language Guide: Structures and Classes

प्रश्न 28. What is the correct way to add a value to this array?

var strings = [1, 2, 3]

All of these answers
strings.append(4)
strings.insert(5, at: 1)
strings += [5]

संदर्भ: The Swift Programming Language: Language Guide: Collection Types: Arrays

प्र29. How many times will this loop be executed?

for i in 0...100 {
  print(i)
}

संदर्भ:

क्यू30. What can AnyObject represent?

An instance of any class
An instance of function type
All of these answers
An instance of an optional type

संदर्भ: The Swift Programming Language: Language Guide: Type Casting: Type Casting for Any and AnyObject

प्रश्न31. What is the value of t after this code is executed?

let names = ["Larry", "Sven", "Bear"]
let t = names.enumerated().first().offset

This code does not compile. / This code is invalid.
0
1
Larry

संदर्भ:

प्र32. What is the value of test after this code executes?

let vt = (name: "ABC", val: 5)
let test = vt.0

ABC
0
5
name

संदर्भ:

प्रश्न 33. What is the base class in this code?

class LSN: MMM {
}

MMM
LSN
There is no base class.
This code is invalid.

संदर्भ: The Swift Programming Language: Language Guide: विरासत: Subclassing

प्रश्न34. 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"

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

संदर्भ: The Swift Programming Language: Language Guide: गुण: Property Observers

क्यू35. 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

संदर्भ: The Swift Programming Language: Language Guide: Initialization: Class Inheritance and Initialization

प्र36. Which object allows you access to specify that a block of code runs in a background thread?

DispatchQueue.visible
DispatchQueue.global
errorExample need to be labeled as throws.
DispatchQueue.background

संदर्भ: Apple Developer: प्रलेखन: Dispatch: DispatchQueue

प्रश्न37. What is the inferred type of x?

let x = ["a", "b", "c"]

String[]
Array<String>
Set<String>
Array<Character>

संदर्भ: The Swift Programming Language: Language Guide: Collection Types: Arrays

प्रश्न 38. What is the value of `oThings` after this code is executed?

let nThings: [Any] = [1, "2", "three"]
let oThings = nThings.reduce("") { "\($0)\($1)" }

11212तीन
115
12तीन
Nothing, this code is invalid.

संदर्भ: Apple Developer: प्रलेखन: तीव्र: सरणी: reduce(_:_:)

प्र39. How would you call a function that throws errors and also returns a value?

!try
try?
try!
?try

संदर्भ: The Swift Programming Language: Language Guide: Error Handling: Handling Errors

क्यू40. What is wrong with this code?

protocol TUI {
  func add(x1: Int, x2: Int) -> Int {
    return x1 + x2
  }
}

Protocol functions cannot have return types.
Protocol functions cannot have implementations.
Nothing is wrong with it.
add is a reserved keyword.

संदर्भ:

प्र41. In this code, what are `wheels` तथा `doors` examples of?

class Car {
  var wheels: Int = 4
  let doors = 4
}

Class members
This code is invalid
Class fields
Class properties

संदर्भ:

प्र42. How do you designated a failable initializer?

You cannot
deinit
init?
init

संदर्भ:

प्रश्न 43. What is printed when this code is executed?

let dbl = Double.init("5a")
print(dbl ?? ".asString()")

five
5a
.asString()
5

संदर्भ:

प्रश्न 44. In the function below, what are `this` तथा `toThat` examples of?

func add(this x: Int, toThat y: Int) { }

None of these answers
Local terms
Argument labels
Parameters names

संदर्भ: The Swift Programming Language: Language Guide: कार्यों

क्यू45. What is wrong with this code?

for (key, value) in [1: "one", 2: "two"] {
  print(key, value)
}

The interaction source is invalid
The interaction variable is invalid
There is nothing wrong with this code
The comma in the print is misplaced

संदर्भ: The Swift Programming Language: Language Guide: बहाव को काबू करें: For-In Loops

प्र46. Which of these choices is associated with unit testing?

XCTest
All of these answers
@testable
XCTAssert

संदर्भ:

प्रश्न 47. नीचे दिए गए कोड में, what is width an example of?

class Square {
  var height: Int = 0
  var width: Int {
    return height
  }
}

This code contains error
A closure
A computed property
Lazy loading

संदर्भ:

प्रश्न 48. What data type is this an example of?

let vals = ("val", 1)

एक शब्दकोष
A tuple
An optional
This code contains error

संदर्भ:

प्र49. What is wrong with this code?

var x = 5
x = 10.0

You cannot assign a Double to a variable of type Int
x is undefined
x is a constant
x has no type

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें

क्यू50. What will this code print to the console?

var items = ["a": 1, "b": 2, "c": "test"] as [String: Any]
items["c"] = nil
print(items["c"] as Any)

Any
परीक्षण
1,2,3
nil

संदर्भ:

प्रश्न51. What is wrong with this code?

let val = 5.0 + 10

There is nothing wrong with this code
val is a constant and cannot be changed
5.0 तथा 10 are different types
There is no semicolon

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Type Safety and Type Inference

प्रश्न52. How many parameters does the initializer for Test have?

struct Test {
  var score: Int
  var date: Date
}

Zero
This code contains an error
Two
Structs do not have initializers

संदर्भ: The Swift Programming Language: Language Guide: Initialization

प्रश्न53. What prints to the console when executing this code?

let x = try? String.init("test")
print(x)

nil
Nothing – this code contains an error
ऐच्छिक(“परीक्षण”)
परीक्षण

संदर्भ:

प्रश्न54. How can you sort this array?

var vals = [1, 2, 3]

vals.sort { $0 < $1 }
vals.sort { (s1, s2) in s1 < s2 }
vals.sort(by: <)
All of these answers

संदर्भ: Apple Developer: प्रलेखन: तीव्र: सरणी: क्रम से लगाना()

प्रश्न55. 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

संदर्भ: Apple Developer: प्रलेखन: Dispatch: DispatchQueue: async(समूह:qos:flags:अमल में लाना:)

प्रश्न56. 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

संदर्भ: The Swift Programming Language: Language Guide: Deinitialization

प्रश्न57. How do you declare an optional String?

String?
Optional[String]
[String]?
?String

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Optionals

प्र 58. How many times this code will be executed? / How many times will this loop be performed?

for i in ["0", "1"] {
  print(i)
}

एक
Two
Three
This code does not compile

संदर्भ: The Swift Programming Language: Language Guide: बहाव को काबू करें: For-In Loops

प्रश्न59. What does this code print?

let names = ["Bear", "Tony", "Svante"]
print(names[1] + "Bear")

1Bear
BearBear
TonyBear
Nothing, this code is invalid

संदर्भ:

क्यू 60. What is true of this code?

let name: String?

name can hold only a string value.
name can hold either a string or nil value.
Optional values cannot be let स्थिरांक.
Only non-empty string variables can be stored in name.

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Optionals

प्रश्न 61. What is the value of `val` after this code is executed?

let i = 5
let val = i * 6.0

This code is invalid.
6
30
0

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Type Safety and Type Inference

प्रश्न 62. What does this code print?

enum Positions: Int {
  case first, second, third, other
}

print (Positions.other.rawValue)

3
0
अन्य
nil

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: Raw Values

प्रश्न 63. What is printed to the console when this code is executed?

"t".forEach { (char) in
  print(char)
}

nil
Nothing, since the code contains an error
टी
zero

संदर्भ:

प्रश्न 64. What prints when this code is executed?

let s1 = ["1", "2", "3"]
  .filter { $0 > "0" }
  .sorted { $0 > $1 }
print(s1)

[]
[“3”, “2”, “1”]
[321]
[“1”, “2”, “3”]

संदर्भ:

प्रश्न 65. What enumeration feature allows them to store case-specific data?

Associated values
Integral values
Raw values
Custom values

संदर्भ: The Swift Programming Language: Language Guide: Enumerations: Associated Values

प्रश्न 66. नीचे दिए गए कोड में, AOM must be a(एन)?

class AmP: MMM, AOM { }

Class
Protocol
Enumeration
Struct

संदर्भ:

प्रश्न 67. What is the value of numbers in the code below?

let numbers = [1, 2, 3, 4, 5, 6].filter { $0 % 2 == 0 }

[1, 3, 5]
[]
[2, 4, 6]
nil

संदर्भ: Apple Developer: प्रलेखन: तीव्र: Swift Standard Library: Collections: Sequence and Collection Protocols: अनुक्रम: फ़िल्टर()

प्रश्न 68. What is the type of `vals` in this code?

let vals = ["a", 1, "Hi"]

सरणी(char)
[Any]
सरणी
[Generic]

संदर्भ: The Swift Programming Language: Language Guide: Type Casting

प्रश्न 69. How can you extract val to `x` in tuple `vt`

let vt = (name: "ABC", val: 5)

let x = vt.1
All of these answers
let x = vt.val
होने देना (_, एक्स) = vt

संदर्भ: The Swift Programming Language: Language Guide: मूल बातें: टुपल्स

क्यू 70. What is the type of x?

let x = try? String.init(from: decoder)

String
String?
String!
try?

संदर्भ: The Swift Programming Language: Language Guide: Error Handling: Handling Errors

प्र71. How many times is this loop executed?

let loopx = 5
repeat {
  print (loopx)
} while loopx < 6

Six
Zero
Five
Infinite

संदर्भ: The Swift Programming Language: Language Guide: बहाव को काबू करें: While Loops

प्र72. How many values does vals have after this code is executed?

var vals: Set<String> = ["4", "5", "6"]
vals.insert("5")

This code contains an error.
Eight
Three
चार

संदर्भ: The Swift Programming Language: Language Guide: Collection Types: सेट

प्रश्न 73. What is the base class in this code ?

class LSN: MMM{ }

MMM
LSN
There is no base class.
This code is invalid.

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LinkedIn skill assessment answers and questions — Swift