Simplified Common Lisp reference

Symbol class: Conses, Lists and related functions

Syntax:

Symbol type: function

memberitemlisttest^(keyword)key^(keyword) => tail or NIL

Argument description:

item	an item to be found
list	a list to be searched
test	function key and item comparison
key	function for extracting value before test

MEMBER function searches a list for the first occurrence of an element (item) satisfying the test. Return value is tail of the list starting from found element or NIL when item is not found. See also MEMBER-IF, POSITION, POSITION-IF, FIND and FIND-IF.

(member 1 '(0 1 0 0 0 1 0)) => (1 0 0 0 1 0)
(member 2 '(0 1 0 0 0 1 0)) => NIL
(member #\h '(#\H #\o #\l #\a)) => NIL
(member #\h '(#\H #\o #\l #\a) :test #'char-equal) => (#\H #\o #\l #\a)
(member #\h '(#\H #\o #\l #\a) :key #'char-downcase) => (#\H #\o #\l #\a)

Function index Full documentation for member (HyperSpec)