PPT Slide

Append gives us another way of putting lists together by appending one (or more) lists to the end of the first one specified.

(append LIST1 LIST2 … LISTn )

constructs and returns a new list containing the elements of LIST1, followed by those of LIST2, … , up to LISTn.

(append ’( A B ) ’( C D ) ) returns ( A B C D )

Which is more efficient?

-- consing a new element to the front of a list or

-- appending a new element to the end?