Kotlin Kotlin Collections and Generics 3

Question 1

What does the `reified` keyword enable for type parameters in Kotlin?

Accepted Answer

Allows accessing the actual type at runtime inside an inline function

Answer

Makes the type parameter nullable

Answer

Restricts the type to numeric types

Answer

Forces the type to be serializable

Question 2

What does `sortedBy` do in Kotlin collections?

Accepted Answer

Returns a new sorted list ordered by the result of a selector function

Answer

Sorts a collection in-place by a selector

Answer

Removes duplicates and then sorts

Answer

Sorts elements in descending order

Question 3

What does `zip` do in Kotlin?

Accepted Answer

Combines two collections element-by-element into a list of Pairs

Answer

Compresses a collection to save memory

Answer

Flattens nested collections

Answer

Merges two maps

Question 4

What is the `Set` interface in Kotlin?

Accepted Answer

An unordered collection that does not allow duplicate elements

Answer

An ordered collection that allows duplicates

Answer

A key-value collection

Answer

A sorted list implementation

Question 5

Which function creates a Map in Kotlin from a list of pairs?

Accepted Answer

both a and b are correct

Answer

toMap()

Answer

mapOf()

Answer

pairsToMap()

Question 6

What does `reduce` do differently from `fold` in Kotlin?

Accepted Answer

`reduce` uses the first element as the initial accumulator; `fold` requires an explicit initial value

Answer

`reduce` requires an initial value; `fold` does not

Answer

`reduce` returns a nullable result; `fold` does not

Answer

They are identical