Bob Cain wrote:


I'm very new to R and utterly blown away by not only the language but the unbelievable set of packages and the documentation and the documentation standards and...


I was an early APL user and never lost my love for it and in R I find most of the essential things I loved about APL except for one thing. At this early stage of my learning I can't yet determine if there is a way to effect what in APL was zero index origin, the ordinality of indexes starts with 0 instead of 1. Is it possible to effect that in R without a lot of difficulty?

I come here today from the world of DSP research and development where Matlab has a near hegemony. I see no reason whatsoever that R couldn't replace it with a _far_ better and _far_ less idiosyncratic framework. I'd be interested in working on a Matlab equivalent DSP package for R (if that isn't being done by someone) and one of the things most criticized about Matlab from the standpoint of the DSP programmer is its insistence on 1 origin indexing. Any feedback greatly appreciated.


Thanks,


Bob

Hallo Bob,


in APL we control index origin by "QUAD.IO" and  QUAD.IO \in {0,1}.
Suppose within a function index origin is unknown:
a) If we want to work with origin 0 we write   x[ i  + QUAD.IO ]
b) ... with origin 1 ...  x[ i - !QUAD.IO ]  .

So set: QUAD.IO <- 1 and use a) --- apl-like.

Or define an index shift function:

io.0<-function(ind) ind+1

to be able to type x[io.0(0:5)]

I am shure that your first experiments have been to implement APL functions
like take, drop, rotate, ... and now you are looking for a more elegant way
to manage origin 0 than "+QUAD.IO".

Peter Wolf

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