nthcdr

ToC

Allegro CL

ANSI Common Lisp

14 Conses

14.2 Dictionary of Conses

14.2.31 nthcdr

Function

Syntax:

nthcdr n list

tail

Arguments and Values:

n - a non-negative integer.

list - a list, which might be a dotted list or a circular list.

tail - an object.

Description:

Returns the tail of list that would be obtained by calling cdr n times in succession.

Examples:

 (nthcdr 0 '())   NIL
 (nthcdr 3 '())   NIL
 (nthcdr 0 '(a b c))  (A B C)
 (nthcdr 2 '(a b c))  (C)
 (nthcdr 4 '(a b c))  ()
 (nthcdr 1 '(0 . 1))  1

 (locally (declare (optimize (safety 3)))
   (nthcdr 3 '(0 . 1)))
 Error: Attempted to take CDR of 1.

Exceptional Situations:

Should signal an error of type type-error if n is not a non-negative integer.

For n being an integer greater than 1, the error checking done by (nthcdr n list) is the same as for (nthcdr (- n 1) (cdr list)); see the function cdr.

See Also:

cdr, nth, rest

Allegro CL Implementation Details:

None.