12 - Fundamentals of Functional Programming

Question 1

Explain the purpose of the fold function in a functional programming language.

Answer 1

It reduces a list of values to a single value by applying a combining function.

Question 2

Explain what a higher-order function is.

Answer 2

A function that takes a function as an argument or returns a function as a result.

Question 3

What is map?

Answer 3

A higher-order function that applies a given function to each element of a list, returning a list of results.

eg. map (*2) [1,2,3] outputs [2,4,6]

Question 4

What is filter?

Answer 4

A higher-order function that processes a data structure, typically a list, in some order to produce a new data structure containing exactly those elements of the original data structure that match a given condition.

eg. filter (<5) [1,4,6] outputs [1,4]

Question 5

What is fold?

Answer 5

A higher-order function which reduces a list of values to a single value by repeatedly applying a combining function to the list of values.

Question 6

What is the head of a list?

Answer 6

The first element in the list

eg the head of [1,2,3] is 1

Question 7

What is the tail of a list?

Answer 7

A list containing each element other than the first element of the list

eg the tail of [1,2,3] is [2,3]