Kotlin Kotlin Collections 3

Question 1

What does `associateBy` do in Kotlin?

Accepted Answer

Creates a Map from a collection using a key selector function

Answer

`associateBy` transforms a collection into a `Map<K, T>` using a key selector, where each element becomes a value mapped by the extracted key.

Question 2

Which Kotlin function checks if all elements satisfy a predicate?

Accepted Answer

all

Answer

`all` returns `true` only if every element in the collection satisfies the given predicate.

Question 3

What does `zip` do in Kotlin collections?

Accepted Answer

Combines two collections into a list of pairs

Answer

`zip` combines two collections element by element into a `List>`, stopping at the shorter collection's length.

Question 4

What is the purpose of `takeWhile` in Kotlin?

Accepted Answer

Takes elements from the start while a predicate is true, stopping at the first false

Answer

`takeWhile` returns elements from the beginning of a collection as long as the predicate is satisfied, stopping when it first returns false.

Question 5

Which function partitions a Kotlin collection into two lists based on a predicate?

Accepted Answer

partition()

Answer

`partition` splits a collection into a `Pair, List>` — the first list contains elements matching the predicate, the second contains the rest.

Kotlin Practice Test