Mapcar

[We are grateful to John H. Remmers for allowing material from his programming languages course to be incorporated into this section.]

The MAPCAR form is an "iterator" that applies a function repeatedly, to each element of a list and returns a list of the results. For example:

> (mapcar 'atom '(dog (cat horse) fish))
(t nil t)

> (mapcar (lambda (x) (* x x)) '(4 7 2 9))
(16 49 4 81)