Re: Newbie question: pairswise function application

• To: mathgroup at smc.vnet.net
• Subject: [mg23883] Re: Newbie question: pairswise function application
• From: Avi Mintz <mintza1 at macs.biu.ac.il>
• Date: Thu, 15 Jun 2000 00:51:20 -0400 (EDT)
• Organization: Bar-Ilan University, Ramat-Gan, Israel
• References: <8i1t6n\$jn9@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```sort the list.

Avi

On 12 Jun 2000, Sidney Cadot wrote:

> Hi,
>
> Wandering through the 1500-odd pages of the Mathematica book, I can't
> find the solution to the following rather silly problem:
>
> I have a list L consisting of (a lot of) integers, and I want to apply a
> function f to all pairs of numbers; furthermore, I don't want to
> calculate both f[a,b] and f[b,a]:
>
> L = {1,5,19,100};
>
> ... and I want:
>
> { f[1,5], f[1,19], f[1,100], f[5,19], f[5,100], f[19,100] }
>
> Can anyone please tell me how to do this? I'd prefer a smart solution
> (i.e., not just generating all pairs, then throwing away a lot of them)
> since my lists tend to get rather large.
>
>