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ANSI Common Lisp  14 Conses 14.2 Dictionary of Conses
- Syntax:
-
nth
n list
 object
(setf
(nth n list) new-object)
- Arguments and Values:
-
n - a non-negative integer.
list - a list,
which might be a dotted list or a circular list.
object - an object.
new-object - an object.
- Description:
-
nth locates the nth element of list,
where the car of the list is the "zeroth" element.
Specifically,
(nth n list) ==(car (nthcdr n list))
nth may be used to specify a place to setf.
Specifically,
(setf (nth n list) new-object) ==(setf (car (nthcdr n list)) new-object)
- Examples:
-
(nth 0 '(foo bar baz)) FOO
(nth 1 '(foo bar baz)) BAR
(nth 3 '(foo bar baz)) NIL
(setq 0-to-3 (list 0 1 2 3)) (0 1 2 3)
(setf (nth 2 0-to-3) "two") "two"
0-to-3 (0 1 "two" 3)
- See Also:
-
elt,
first,
nthcdr
- Allegro CL Implementation Details:
-
None.
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