```
λ> sequence [Just 1, Just 2, Just 3]
Just [...
# arrowa
alex.hart
02/02/2018, 12:31 PM Copy code
λ> sequence [Just 1, Just 2, Just 3]
Just [1,2,3]
λ> sequence [Just 1, Nothing, Just 3]
Nothing
λ> sequence . filter (/= Nothing) $ [Just 1, Nothing, Just 3]
Just [1,3]