common-lisp LOOP, a Common Lisp macro for iteration Looping over Sequences
Example
(loop for i in '(one two three four five six)
do (print i))
(loop for i in '(one two three four five six) by #'cddr
do (print i)) ;prints ONE THREE FIVE
(loop for i on '(a b c d e f g)
do (print (length i))) ;prints 7 6 5 4 3 2 1
(loop for i on '(a b c d e f g) by #'cddr
do (print (length i))) ;prints 7 5 3 1
(loop for i on '(a b c)
do (print i)) ;prints (a b c) (b c) (c)
(loop for i across #(1 2 3 4 5 6)
do (print i)) ; prints 1 2 3 4 5 6
(loop for i across "foo"
do (print i)) ; prints #\f #\o #\o
(loop for element across "foo"
for i from 0
do (format t "~a ~a~%" i element)) ; prints 0 f\n1 o\n1 o
Here is a summary of the keywords
| Keyword | Sequence type | Variable type |
|---|---|---|
| in | list | element of list |
| on | list | some cdr of list |
| across | vector | element of vector |
