Partition for splitting in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the partition function do in Kotlin?

It splits a collection into two lists based on a condition: one list with elements that satisfy the condition, and another with elements that don't.

beginner

How do you use partition to separate even and odd numbers from a list?

Use val (evens, odds) = list.partition { it % 2 == 0 }. This creates two lists: evens with even numbers and odds with odd numbers.

intermediate

What is the return type of the partition function?

It returns a Pair<List<T>, List<T>>, where the first list contains elements matching the predicate, and the second list contains the rest.

beginner

Can partition be used on any Kotlin collection?

Yes, partition works on any Iterable, like lists and sets.

intermediate

What happens if no elements satisfy the condition in partition?

The first list in the returned pair will be empty, and the second list will contain all elements.

What does Kotlin's partition function return?

A A single list with filtered elements

B A map of elements grouped by condition

C A pair of lists splitting elements by a condition

D A boolean indicating if any element matches

partition returns a Pair of two lists: one with elements that satisfy the condition, and one with those that don't.

How do you capture the two lists returned by partition?

A Using destructuring declaration like <code>val (yes, no) = ...</code>

B Using a single list variable

C Using a map variable

D Using a boolean variable

You use destructuring to get both lists from the Pair returned by partition.

If you want to split a list of numbers into positives and non-positives, which predicate fits partition?

A <code>{ it >= 0 }</code>

B <code>{ it < 0 }</code>

C <code>{ it == 0 }</code>

D <code>{ it > 0 }</code>

The predicate { it > 0 } selects positive numbers for the first list.

What type of collections can use partition in Kotlin?

A Any <code>Iterable</code> like lists and sets

B Only arrays

C Only maps

D Only sequences

partition works on any Iterable, including lists and sets.

What will be the size of the first list if no elements satisfy the partition condition?

A Undefined

B Zero (empty list)

C One

D Same as original list

If no elements match, the first list is empty.

Explain how Kotlin's partition function works and give a simple example.

Think about separating items based on a yes/no question.

Describe the return type of partition and how to access the two lists it produces.

Remember how Kotlin lets you unpack pairs easily.