nth_car, nth_cdr

Arguments

Returns

An element of the list, or nil.

Description

The nth_car and nth_cdr functions iteratively apply the car and cdr functions to a list. If the list argument is not a list, or if the result of any subsequent application of car or cdr is not a list, the result is nil. If the number of applications is less than or equal to 0, the result is the original list.

Example

Gamma> c = list (list(list(list(4,5))));
((((4 5))))
Gamma> nth_car(c,2);
((4 5))
Gamma> nth_car(c,4);
4

Gamma> b = list (6,7,8,9,10);
(6 7 8 9 10)
Gamma> nth_cdr (b,2);
(8 9 10)
Gamma> nth_cdr(b,5);
nil
Gamma> nth_cdr(b,4);
(10)
Gamma> 
		

See Also

cons, list, car, cdr