- memq obj listprocedure
- memv obj listprocedure
- member obj listprocedure
These procedures return the first sublist of list whose car is obj, where the sublists of list are the non-empty lists returned by (list-tail list k) for k less than the length of list. If obj does not occur in list, then #f (not the empty list) is returned. Memq uses eq? to compare obj with the elements of list, while memv uses eqv? and member uses equal?.
(memq 'a '(a b c)) ===> (a b c) (memq 'b '(a b c)) ===> (b c) (memq 'a '(b c d)) ===> #f (memq (list 'a) '(b (a) c)) ===> #f (member (list 'a) '(b (a) c)) ===> ((a) c) (memq 101 '(100 101 102)) ===> unspecified (memv 101 '(100 101 102)) ===> (101 102)