EXO3

(defun my-assoc (cle a-liste) 
(car (remove nil (mapcar( lambda( x )( if (equal  cle (car x) ) x )) a-liste ))))
(print(my-assoc 'Pierre  '((Yolande  25) (Pierre  22) (Julie  45))))   
(print (my-assoc 'Yves  '((Yolande  25) (Pierre  22) (Julie  45))) )

(defun cles (a-liste)
  (mapcar #'car a-liste)
)

(print (cles '((Yolande 25) (Pierre 22) (Julie 45))))

 
   
(defun creation (cles valeurs)
  (mapcar #'list cles valeurs))

(print (creation '(Yolande Pierre Julie) '(25 22 45)))