<cl> (find 3 '(2 -3.0 1 2 3 -3 4 5)) 3 <cl> (find 3.0 '(2 -3.0 1 2 3 -3 4 5)) NIL <cl> (find 3.0 '(2 -3.0 1 2 3 -3 4 5) :test #'eql) NIL <cl> (find 3.0 '(2 -3.0 1 2 3 -3 4 5) :test #'equal) NIL <cl> (find 3.0 '(2 -3.0 1 2 3 -3 4 5) :test #'=) 3 <cl> (find 3.0 '(2 -3.0 1 2 3 -3 4 5) :test #'equalp) 3 <cl> (find 3 '(2 -3.0 1 2 3 -3 4 5) :test #'<) 4 <cl> (find 3 '(2 -3.0 1 2 3 -3 4 5) :key #'abs) 3 <cl> (find 3 '(2 -3.0 1 2 3 -3 4 5) :key #'abs :test #'equalp) -3.0findはfind-ifを用いて作ることができます.
<cl> (defun my-find (y data) (find-if #'(lambda (x) (eq x y)) data)) MY-FIND <cl> (my-find 'a '(a b c)) A <cl> (my-find 'd '(a b c)) NIL