Réponses et questions sur l'évaluation des compétences LinkedIn

“Rapide has emerged as a powerful and intuitive programming language for developing iOS, macOS, and watchOS applications, offering developers a modern and efficient platform for building innovative software. Dans ce guide complet, nous sommes ravis de présenter une série de questions d'évaluation des compétences et réponses spécialement conçu pour Rapide utilisateurs.

Whether you’re a seasoned developer looking to expand your capabilities or a beginner aiming to understand the basics of this powerful language, cette ressource est conçue pour vous aider à maîtriser Rapide et ses applications. Rejoignez-nous pour explorer les concepts fondamentaux de Rapide programmation, including optionals, closures, protocols, et plus, 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
Mission
Initialization

Référence: The Swift Programming Language: Language Guide: Les bases: Constants and Variables

Q2. What is the error in this code?

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

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

Référence: The Swift Programming Language: Language Guide: Control Flow: Early Exit

T3. What is the raw/underlying type of this enum?

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

There is none
String
Any
Int

Référence: The Swift Programming Language: Language Guide: Enumerations: Raw Values

T4. 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.
Toutes ces réponses.

Référence: Apple Developer: Documentation: Dispatch: Dispatch Group

Q5. What is this code an example of?

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

String interpolation
String compilation
Method chaining
Concaténation de chaînes

Référence: 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

Référence: Apple Developer: Documentations: Rapide: Déployer: trier()

Q7. What does this code print?

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

Dictionary<String, Any>
Dictionary
Error
Thing

Référence: The Swift Programming Language: Language Reference: Les types: Type Identifier

Q8. What is the value of y?

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

This code contains an error
1
2
nil

Toutes les transactions commerciales ont été expliquées par cartographie dans SAP IM et son module intégré
dropFirst() de 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.
Référence

Q9. What is the value of test in this code?

var test = 1 == 1

true
YES
1
This code contains an error

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

Q10. What is the value of y?

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

5
0
nil
This code contains an error

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

Vous devrez atteindre au moins. 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.

Référence: The Swift Programming Language: Language Guide: Les fonctions: Function Types

Q12. 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)

Référence: The Swift Programming Language: Language Guide: Les fonctions: Function Argument Labels and Parameter Names

Q13. The Codable protocol is _?

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

Références:

Q14. What is the type of value1 in this code?

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

String
Int
null
test.count

Référence: 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 is as escaping?

When it’s executed after the function returns
When it’s scope is undefined
When it’s lazy loaded
Toutes ces réponses

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

Q16. 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.

Référence: 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) -> String in
  return s.uppercased()
}

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

Q18. 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

Référence: The Swift Programming Language: Language Guide: Les bases: Type Safety and Type Inference

Q19. 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.

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

Q20. didSet and willSet are examples of _?

Property observers
Key properties
Toutes ces réponses
newOld value calls

Référence: The Swift Programming Language: Language Guide: Propriétés

Q21. 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.

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

Q22. How many values does vals have after this code is executed?

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

Three
Quatre
Eight
This code contains an error.

Référence: 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 ou 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.

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

Q24. What is wrong with this code?

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

Ce 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.

Référence: The Swift Programming Language: Language Guide: Les bases: Optionals

Q25. Which code snippet correctly creates a typealias closure?

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

Référence: 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

Référence: The Swift Programming Language: Language Guide: Méthodes: Instance Methods

Q27. All value types in Swift are _ sous la capuche?

Structs
Des classes
Optionals
Generics

Référence: 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]

Toutes ces réponses
strings.append(4)
strings.insert(5, at: 1)
strings += [5]

Référence: The Swift Programming Language: Language Guide: Collection Types: Qu'est-ce que le test logiciel

Q29. How many times will this loop be executed?

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

Références:

Q30. What can AnyObject represent?

An instance of any class
An instance of function type
Toutes ces réponses
An instance of an optional type

Référence: 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

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

Références:

Q32. What is the value of test after this code executes?

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

ABC
0
5
name

Références:

sur un ___. What is the base class in this code?

class LSN: MMM {
}

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

Référence: The Swift Programming Language: Language Guide: Héritage: 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"

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

Référence: The Swift Programming Language: Language Guide: Propriétés: Property Observers

Chaque calque et ceux-ci sont tous alignés en même temps. 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

Référence: 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
errorExample need to be labeled as throws.
DispatchQueue.background

Référence: Apple Developer: Documentation: Dispatch: DispatchQueue

Q37. What is the inferred type of x?

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

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

Référence: The Swift Programming Language: Language Guide: Collection Types: Qu'est-ce que le test logiciel

Q38. What is the value of `oThings` after this code is executed?

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

11212Trois
115
12Trois
Rien, this code is invalid.

Référence: Apple Developer: Documentation: Rapide: Déployer: reduce(_:_:)

Q39. How would you call a function that throws errors and also returns a value?

!try
try?
try!
?try

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

Q40. 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.

Référence:

Q41. In this code, what are `wheels` et `doors` examples of?

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

Class members
This code is invalid
Class fields
Class properties

Référence:

Q42. How do you designated a failable initializer?

You cannot
deinit
init?
init

Référence:

Q43. What is printed when this code is executed?

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

five
5a
.asString()
5

Référence:

Q44. In the function below, what are `this` et `toThat` examples of?

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

None of these answers
Local terms
Argument labels
Parameters names

Référence: The Swift Programming Language: Language Guide: Les fonctions

Q45. 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

Référence: The Swift Programming Language: Language Guide: Control Flow: For-In Loops

Q46. Which of these choices is associated with unit testing?

XCTest
Toutes ces réponses
@testable
XCTAssert

Référence:

Q47. In the code below, 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

Référence:

Q48. What data type is this an example of?

let vals = ("val", 1)

Un dictionnaire
A tuple
An optional
This code contains error

Référence:

Q49. 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

Référence: The Swift Programming Language: Language Guide: Les bases

Q50. 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
tester
1,2,3
nil

Références:

Q51. 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 et 10 are different types
There is no semicolon

Référence: The Swift Programming Language: Language Guide: Les bases: Type Safety and Type Inference

Q52. 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

Référence: 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)

nil
Rien – this code contains an error
Optionnel(“tester”)
tester

Références:

Q54. 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: <)
Toutes ces réponses

Référence: Apple Developer: Documentation: Rapide: Déployer: trier()

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

Référence: Apple Developer: Documentation: Dispatch: DispatchQueue: async(groupe:qos:flags:exécuter:)

Q56. When is deinit called?

When a class instance needs memory
Toutes ces réponses
When the executable code is finished
When a class instance is being removed from memory

Référence: The Swift Programming Language: Language Guide: Deinitialization

Q57. How do you declare an optional String?

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

Référence: The Swift Programming Language: Language Guide: Les bases: 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)
}

Un
Two
Three
This code does not compile

Référence: 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")

1Bear
BearBear
TonyBear
Rien, this code is invalid

Références:

Q60. 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 constantes.
Only non-empty string variables can be stored in name.

Référence: The Swift Programming Language: Language Guide: Les bases: Optionals

Q61. 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

Référence: The Swift Programming Language: Language Guide: Les bases: Type Safety and Type Inference

Q62. What does this code print?

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

print (Positions.other.rawValue)

3
0
autre
nil

Référence: The Swift Programming Language: Language Guide: Les bases: Raw Values

Q63. What is printed to the console when this code is executed?

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

nil
Rien, since the code contains an error
t
zéro

Références:

Q64. 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”]

Références:

Q65. What enumeration feature allows them to store case-specific data?

Associated values
Integral values
Raw values
Custom values

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

Q66. In the code below, AOM must be a(n)?

class AmP: MMM, AOM { }

Class
Protocol
Enumeration
Struct

Références:

Q67. 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

Référence: Apple Developer: Documentation: Rapide: Swift Standard Library: Collections: Sequence and Collection Protocols: Séquence: filtre()

Q68. What is the type of `vals` in this code?

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

Déployer(char)
[Any]
Déployer
[Generic]

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

Q69. How can you extract val to `x` in tuple `vt`

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

let x = vt.1
Toutes ces réponses
let x = vt.val
laisser (_, X) = vt

Référence: The Swift Programming Language: Language Guide: Les bases: Tuples

Q70. What is the type of x?

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

Chaîne
Chaîne?
Chaîne!
essayer?

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

Q71. How many times is this loop executed?

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

Six
Zero
Five
Infinite

Référence: The Swift Programming Language: Language Guide: Control Flow: While Loops

Contrôle des risques liés à la sécurité des processus. 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
Quatre

Référence: The Swift Programming Language: Language Guide: Collection Types: Sets

Q73. What is the base class in this code ?

class LSN: MMM{ }

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

Auteur

Hélène Bassey

salut, I'm Helena, un écrivain de blog passionné par la publication de contenus perspicaces dans le créneau de l'éducation. Je crois que l'éducation est la clé du développement personnel et social, et je souhaite partager mes connaissances et mon expérience avec des apprenants de tous âges et de tous horizons. Sur mon blog, vous trouverez des articles sur des sujets tels que les stratégies d'apprentissage, éducation en ligne, orientation professionnelle, et plus. J'apprécie également les commentaires et suggestions de mes lecteurs, alors n'hésitez pas à laisser un commentaire ou à me contacter à tout moment. J'espère que vous apprécierez la lecture de mon blog et que vous le trouverez utile et inspirant.
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Réponses et questions sur l'évaluation des compétences LinkedIn — Swift