12.2 Writing functional programs

Question 1

What does the Map function do?

Answer 1

Takes a second function and applies it to a list of elements before returning the new list

Question 2

What does the filter function do?

Answer 2

Returns the elements of the list which adhere ti the condition given. It is IN rather than a filter OUT.

Question 3

What does the fold function do?

Answer 3

Reduce the list to a single value. Known as reducing. The function needs an operator (+,-) a starting number and a list. The type - left or right - determines how the recursion will work.