LinkedIn skill assessment answers and questions — Scala

“Scala has emerged as a powerful and versatile programming language that combines functional and object-oriented paradigms, offering developers a robust platform for building scalable and efficient applications. في هذا الدليل الشامل, نحن متحمسون لتقديم مجموعة منسقة من أسئلة تقييم المهارات و الإجابات إلى عن على Scala.

Whether you’re a seasoned developer looking to enhance your skills or a newcomer eager to explore the world of functional programming, this resource is designed to help you master Scala and its innovative features. انضم إلينا ونحن نتعمق في أساسيات Scala برمجة, including immutability, pattern matching, وظائف ذات ترتيب أعلى, و اكثر, empowering you to leverage the full potential of this dynamic language.”

Q1. Scala bytecode can run on top of Java VM. What is the fundamental difference between Java object.clone() and Scala object.copy()?

One is a Java object, the other is a Scala object.
Git Workflow لمهندسي Azure DevOps() will copy class structures but not the data, while copy() will also copy data into new objects.
ليس هناك فرق.
ينسخ() allows you to change values during the copying process; Git Workflow لمهندسي Azure DevOps() لا.

Q2. What value does this code return?

val m1 = Map("a"->1,"b"->2,"c"->3)
m1("a")

Q3. What is one way to avoid low-level parallelization details?

مناد
literal functions
partially applied functions
parallel collections

Q4. What do you use in ScalaTest to see a detailed diagram of error messages when a test fails?

ArgumentExceptions
AssertionException
DiagrammedAssertions
JUnit

Q5. What data type would you use to store an immutable collection of objects that contain a fixed number of varying types?

مجموعة مصفوفة
ImmutableCollection
قائمة
مترابطة بيانية

Q6. After defining a function in the interpreter, Scala returns the following. ماذا يكون ال `()` يشير?

myfnc: ()Unit

The function has no side effects.
The function takes no parameters.
The function returns no value.
Returning unit types to the function is a closures.

Q7. What type of number is 1234.e5?

السداسي عشري
قصيرة
floating point
طويل

Q8. When you convert a map to a list using the `toList` method of the map, the result will be of which type?

List[(String, String)]
List[(Array, Array)]
List[(Collection, Collection)]
List

Q9. What type of object does this code create?

val x = (1234, "Active")

قائمة
خريطة
مترابطة بيانية
مجموعة مصفوفة

Q10. Which is a subclass of all classes?

AnyVal
AnyRef
Method
Null

Null in Scala Standard library. The question is a bit incorrect – Null is a subtype of every type except those of value classes

سوف تحتاج إلى تحقيق ما لا يقل عن. For the for-yield construct, is the scope separate between for-body and yield-body?

Yes and no. It is different depending on the for construct and what it does.
نعم فعلا, because the for section does not expose its scope.
لا, because for-yield shares the same scope, even though they are within separate curly braces.
نعم فعلا, because they are within different curly braces.

مثال: yield-body has access to the e variable from the for-body

val a = Array(1, 2, 3, 4, 5)
for {
     e <- a if e > 2
} yield e

س 12. What is one way to implement pattern matching on methods?

using regex
using monads
using string matching
using case classes

ملحوظة: ambiguous question, it’s not clear what kind of pattern matching is meant here.

Q13. What is the value of z after executing this code?

val y = List('a','b')
val z = y::List('c')

قائمة(ا,ب,ج)
قائمة(قائمة(ا, ب), ج)
قائمة(ج,ا,ب)
قائمة(ج,قائمة(ا,ب))

س 14. What term is used to specify a precondition?

assert
يتطلب
precondition
mustHave

س 15. Which Scala type may throw an exception or a successfully computed value, and is commonly used to trap and propagate errors?

scala.util.ExceptionHandling
scala.Catch.Throw
scala.exception.TryFinally
scala.util.Try

scala.util.Try

س 16. What is the data type of y after this code is executed?

val y = (math floor 3.1415 * 2)

قصيرة
مزدوج
int
bigInt

Q17. When using pattern matching, which character matches on any object?

Pattern Matching

س 18. You have created an array using val. Can you change the value of any element of the array—and why or why not?

نعم فعلا, the reference to the array is immutable, so the location that the array points to is immutable. The values in the array are mutable.
The 0th element is immutable and cannot be modified. All other elements can be modified.
نعم فعلا, val does not make arrays immutable.
لا, val makes the array and values of the array immutable.

تتم محاذاة كل طبقة وهذه كلها في نفس الوقت:

val a1 = Array(1, 2, 3)
a1{1} = 3 // OK
a1 = Array(1, 3, 3) // error: reassignment to val

Q19. What is the output of this function?

def main () {
     var a = 0
     for (a<-1 until 5){println(a)}

1,2,3,4,5
0,1,2,3,4
1,2,3,4
2,3,4,5

س 20. What do you call objects with immutable state?

singletons
stationary objects
functional objects
fixed objects

ملحوظة: singletons may have mutable state

س 21. You have written a Scala script. How would you access command-line arguments in the script?

use array named args
use tuple named args
use numbered variables with a _ prefix for example _ 1, _ 2, _ 3
use numbered variables with a $ prefix – فمثلا $1, $2, $3

Q22. What does this code return? `val x = 3; if (x > 2) x = 4 else x = x*2`

4
an error
6
3

Q23. Which statement returns a success or a failure indicator when you execute this code?

val MyFuture = Future {runBackgroundFunction() }

myFuture.onComplete
myFuture(status)
myFuture.Finished
اكتمال(myFuture)

س 24. To denote a parameter that may be repeated, what should you place after type?

Q25. What is called when a superclass has more than one subclass in Scala?

polyinheritance
multilevel inheritance
multimode inheritance
hierarchical inheritance

س 26. One way to improve code reliability is to use `__` , which will evaluate a condition and return an error if the condition is violated.

الحزم
polymorphisms
assertions
traits

Q27. Which statement about if-else-if-else statements is true?

If the first else-if does not succeed, then no other else-ifs are tested.
If an else-if does not succeed, then none of the remaining else-if statements or elses will be tested.
All else-if statements are tested in all cases.
If an else-if succeeds, then none of the remaining else-if statements or elses will tested.

س 28. What do you call the process of changing the definition of an inherited method?

recursive methods
currying methods
redefining methods
overriding methods

س 29. To denote a parameter that may be repeated, what should you place after the type?

Repeated Parameters in Scala

Q30. What is the code below equivalent to?

myClass.foreach(println _)

myClass.foreach(println ())
myClass.foreach(print NIL)
myClass.loop(println ())
myClass.foreach(x => println(x))

س 31. What is an advantage of an immutable object?

Immutable objects use less memory than their mutable counterparts.
Immutable objects do not require error handling.
Immutable objects can be used in classes, mutable objects cannot.
Immutable objects are threadsafe.

Q32. You want to create an iteration loop that tests the condition at the end of the loop body. Which iteration would you use?

do-while loop
حائط اللوب
Tuples وهي وظائف
do-until loop

على ___. What can you use to make querying a database more efficient, by avoiding the need to parse the SQL string every time a query is executed from Scala?

database driver
الإتصال
prepared statement
SQL view

PreparedStatement from Java which is also used in Scala

س 34. Which is ليس a member of the collections hierarchy?

جلس
Seq
Hash
خريطة

تتم محاذاة كل طبقة وهذه كلها في نفس الوقت. Which term makes the contents of packages available without prefixing?

استعمال
تتضمن
يستورد
assertion

Q36. If you wanted to find the remainder after division, what operator would you use?

Q37. What are defined inside a class definition?

طريقة
fields and methods
مجالات, أساليب, and packages
مجالات

Q38. What defines methods and fields that can then be reused by mixing into classes?

singleton
assertion
trait
monad

Q39. When do you need to explicitly state the return type in a function definition?

when the function has no side effects
when the function returns a Unit type
when the function is recursive
when the function has side effects

س 40. Why would you make a field private?

so only methods in the same file can access the field
so only methods in the same package can access the field
so only methods in the same class could access the field
so only methods defined in a Java class can access the field

س 41. What’s the difference between `.equals` و `==`?

They do the exact same thing
== won’t work on objects
== cannot be applied to String
== is a wrapper of .equals() and checks for nulls

مصدر:

س 42. What is denotes the intersection between two sets?

مصدر:

س 43. What do you call a function defined in a block?

private function
block function
local function
طريقة

A function defined within a block of code, such as within a method or another function, is called a local function. This is because it is only visible and accessible within the scope of the block in which it is defined, and is not accessible outside of that block.

س 44. What do you call a Scala method that is parametrized by type as well as by value?

multimode method
polymorphic method
closure
collection method

س 45. What type of exception is thrown when a precondition is violated?

IllegalArgumentException
NumberFormatException
NullPointerExcepetion
MalformedParameterException

س 46. In scala what is precondition?

a constraint on where a method may be called from
a constraint on values passed to a methode constructor
a class of predifined error messages
a class of Boolean operators

Q47. What would you change in this code to make it execute in parallel?

 val myNums = (1 to 500).toList
 list.map(_ + 1)

يتغيرون list.map إلى list.par.map.
يتغيرون toList إلى toListPar
يتغيرون val إلى val.par
يتغيرون toList إلى toParallelList

س 48. What is a free variable?

a variable defined outside a function
a variable referenced in a function that is not assigned a value by that function
a variable that has a global scope
a variable defined in a class and available to all methods in that class

Q49. What’s the best way to execute code in the background in a separate thread?

AltThread
AltFuture
AltProcess
مستقبل

س 50. What value does this code return?

x= List(1,2,4); x(1)?

(1,2,4)
1
Nil
2

س 51. Which data type does Scala use instead of null for optional values?

Nil
Option
Singleton
مجموعة

In Scala, the Option data type is used instead of null for optional values. It is a container that can either hold a value or be empty, and it is used to represent the presence or absence of a value. This makes it safer to work with than using null, as it eliminates the risk of null pointer exceptions.

Q52. What is equivalent to this code?

s"Foo $a?"

“Foo ” + ا + “?”

Q53. Which expression is one way to iterate over a collection and generate a collection of each iteration’s result?

for-yield
for-collect
for-collect until
collectuntil
for-yield is one way to iterate over a collection and generate a collection of each iteration’s result. The for loop with the yield keyword is used to iterate over a collection and generate a new collection with the results of each iteration.

س 54. Which statement accesses the third element of an array named foo?

foo[2]
foo(3)
foo[3]
foo(2)
In many programming languages, arrays are indexed starting at 0, so the first element of the array is at index 0, the second element is at index 1, وما إلى ذلك وهلم جرا. وبالتالي, to access the third element of an array named “foo”, you would use the index 2 (since the array is indexed starting at 0). This can be done using the syntax foo[2] or foo(2) depending on the programming language. In some languages like Java, you can use foo[2] or foo[3] to access the third element.

Q55. What data type would you use to store an immutable collection of objects when you don’t know how many members will be in the collection?

مترابطة بيانية
قائمة
Object
مجموعة مصفوفة
You would use a List data type to store an immutable collection of objects when you don’t know how many members will be in the collection. Lists are indexed collections of elements that can be accessed by their position in the list, and they are commonly used to store collections of items that need to be processed in order. بالإضافة إلى, Lists are immutable, which means that their elements cannot be modified once they have been created, making them ideal for use cases where data integrity is important.

س 56. From where do all classes in Scala inherit?

AnyRef
AnyColl
AnyVal
AnyClass
All classes in Scala inherit from the AnyRef class by default. AnyRef is the base class for all reference types in Scala, and it is equivalent to the java.lang.Object class in Java. AnyVal is the base class for all value types in Scala, and Any is the base class for all types in Scala.

Q57. In Scala, what is a precondition?

A class of boolean operators
A class of predefined error messages
A constraint on values passed to a method or constructor
A constraint on where a method may be called from
A precondition in Scala is a constraint on the input values passed to a method or constructor, specifying the conditions that must be met for the method or constructor to execute correctly. It is used to check the validity of input values before the method or constructor is executed, and can be used to ensure that the method or constructor is called with the correct arguments.

س 58. Which code sample will print the integers 1 عبر 4, each on a separate line?

إلى عن على(أنا <- 0 إلى 4) println(أنا)
إلى عن على(أنا <- 0 إلى 3) println(i+1)
إلى عن على(أنا <- 1 إلى 8 if i < 5) println(أنا)
إلى عن على(أنا <- 1 إلى 4) println(أنا)
The correct answer is for(أنا <- 0 إلى 3) println(i+1) because it will start the iteration from 0 and end at 3, incrementing the value by 1 each time and printing it.

س 59. Which operator should you use to take the intersection of two sets?

&
||
&&
%
ال & or intersect method can be used to take the intersection of two sets in Scala.

س 60. Which data type does Scala use instead of null for optional values?

Nil
Option
Singleton
مجموعة
In Scala, the Option data type is used instead of null for optional values. It is a container that can either hold a value or be empty, and it is used to represent the presence or absence of a value. This makes it safer to work with than using null, as it eliminates the risk of null pointer exceptions.

س 61. What is the difference between a Scala trait and an interface?

A trait can have concrete implementations, while an interface cannot.
An interface can have concrete implementations, while a trait cannot.
Traits can be mixed together, while interfaces cannot.
Interfaces can be mixed together, while traits cannot.

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LinkedIn skill assessment answers and questions — Scala