The average below isn't tacit since it refers to the argument of the
function, x. It's true that J's [ and ] do similar things, but with
entirely different semantics: they are actually functions of one or two
arguments that return the appropriate argument. Perhaps it's not so evident
here, but in J you could also write something like (- * +) and execute it
on two variables to multiply their sum and their difference. Q would
require {(x-y) * (x+y)} , which is unwieldy.
Marshall
On Tue, Jan 17, 2012 at 9:14 PM, Colin Ward <ward...@gmail.com> wrote:
> Thank you to everyone for your replies. I have taken the advice of the
> first response and am trying both, starting with q.
>
> On tacit programming, i think i have found it is possible in q, and it does
> have currying. They have default (implicit?) arguments x and y to refer to
> the first and second args in a monad/dyadic function. similar to j's [
> and ] operators?
>
> So by my reckoning this code below is an example of tacit average in q?
> q) is the prompt...
>
>
> q)average:{ (sum x) % count x}
> q)average[2 3 4]
> 3f
> q)average[2 3 4 5]
> 3.5
>
> hope my other three questions are as easy to figure out...
>
> On 17 January 2012 00:59, Boyko Bantchev <boyk...@gmail.com> wrote:
>
> > On 16 January 2012 18:11, Kim Kuen Tang <kuent...@vodafone.de> wrote:
> > >
> > > I tried to calculate the mean in K using tacit programming.
> > > (+/%# ) !10
> > > But it is not working. Can you show how to program it in K?
> >
> > There are no forks like +/%# in K. Instead, you can do:
> > avg: %/(+/;#:)@\:
> > avg 2 3 7
> > 4.0
> > avg' (2 3 7; 5 6)
> > 4 5.5
> >
> > Or, you can define a `fork' yourself:
> > fork: {[f;g;h;x] g[f[x];h[x]]}
> > which itself is non-tacit, but allows tacit definitions such as:
> > avg: fork[+/;%;#:;]
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> >
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
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For information about J forums see http://www.jsoftware.com/forums.htm
