List Operations

List Operations

Haskell's standard library has many useful list functions:

map and filter

map applies a function to every element. filter keeps elements that satisfy a predicate:

map (*2) [1,2,3]        -- [2,4,6]
filter even [1..10]     -- [2,4,6,8,10]

take and drop

take 3 [1..10]   -- [1,2,3]
drop 3 [1..10]   -- [4,5,6,7,8,9,10]

zip

Pairs up elements from two lists:

zip [1,2,3] ["a","b","c"]
-- [(1,"a"),(2,"b"),(3,"c")]

reverse

reverse [1..5]   -- [5,4,3,2,1]

Your Task

Starting from [1..20]:

1. Filter to keep only odd numbers
2. Take the first 5 of those
3. Print the result