6.1.3.1 Examples of COLLECT clause

;; Collect all the symbols in a list.
 (loop for i in '(bird 3 4 turtle (1 . 4) horse cat)
       when (symbolp i) collect i)
=>  (BIRD TURTLE HORSE CAT)
 
;; Collect and return odd numbers.
 (loop for i from 1 to 10
       if (oddp i) collect i)
=>  (1 3 5 7 9)
 
;; Collect items into local variable, but don't return them.
 (loop for i in '(a b c d) by #'cddr
       collect i into my-list
       finally (print my-list))
>>  (A C) 
=>  NIL