Re: LISP Questions - random, random elements and memory management

[Kevin Rodgers <kevin.d.rodgers@gmail.com>]

Jeff Clough wrote:
> From: Jeff Clough <jeff@chaosphere.com>
> Date: Wed, 18 Nov 2009 07:54:28 -0500 (EST)
> 
>> (defun get-random-element (list)
>>   "Returns a random element of LIST."
>>   (if (not (and (list) (listp list)))
>>       (nth (random (1- (1+ (length list)))) list)
>>     (error "Argument to get-random-element not a list or the list is empty")))
>>
> 
> Yay for not being awake!  The above should be this:
> 
> (defun get-random-element (list)
>   "Returns a random element of LIST."
>   (if (and list (listp list))
>       (nth (random (1- (1+ (length list)))) list)
>     (error "Argument to get-random-element not a list or the list is empty")))

Is (1- (1+ (length list))) not exactly the same as (length list)?

-- 
Kevin Rodgers
Denver, Colorado, USA