Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!mit-eddie!ll-xn!ames!amdcad!sun!pitstop!robv
From: robv@pitstop.UUCP (Rob Vollum)
Newsgroups: comp.lang.lisp
Subject: Re: Summing a list
Message-ID: <248@pitstop.UUCP>
Date: 27 Oct 88 13:54:30 GMT
References: <1131@amelia.nas.nasa.gov> <5671@eagle.ukc.ac.uk> <10794@srcsip.UUCP>
Reply-To: robv@pitstop.UUCP (Rob Vollum)
Organization: Sun Microsystems, Inc., Lexington, MA
Lines: 27

In article <10794@srcsip.UUCP> rogers@eagle.UUCP (Brynn Rogers) writes:

> I Have a silly question.   I need to take the sum of a list 
> of numbers.
> (SETQ NUMLIST '(1 2 3 6 7))
> This is quite simple, really, but what is the BEST way to do it?
> I like: 
> 
> (EVAL (CONS '+ NUMLIST))
>
> But someone else says this would be faster::
>  
	[...iteration and recursion code deleted...]

How about (apply #'+ numlist)?

Besides being simple and clear, it is usually only a bit more
overhead than an explicit call to the function being APPLY'd. In
many cases, if the compiler is clever (and/or the programmer
makes declarations about the function being APPLY'd), it is *no*
additional overhead.

Rob Vollum
Sun Microsystems
Lexington, MA

sun!sunne!robv  or  rvollum@sun.com