R help - Oct 2003 - 2 questions regarding base-n and identifing digits

Dear listers,

I have two questions:
(1)
Is there a way in R to change the base-n of the calculations. I wnat to run
some calculations either in binary (base-2) or base-4. Is there a way to
specify that in R - to chnage from the decimal?

(2)
I also want to extract the digits from a larger number and store them as a
vector.
I could do it through converting top string, parsing the string and
converting back. Is there another way.
It would look something like that:
> a<-1234
> a
[1] 1234
> b<-foo(a)
> b
     [,1] [,2] [,3] [,4]
[1,]    1    2    3    4

Thanks!

Andrej

_________
Andrej Kveder, M.A.
researcher
Institute of Medical Sciences SRS SASA; Novi trg 2, SI-1000 Ljubljana,
Slovenia
phone: +386 1 47 06 440   fax: +386 1 42 61 493

	[[alternative HTML version deleted]]

> From: Andrej Kveder [mailto:andrejk at zrc-sazu.si] 
> 
> Dear listers,
> 
> I have two questions:
> (1)
> Is there a way in R to change the base-n of the calculations. 
> I wnat to run some calculations either in binary (base-2) or 
> base-4. Is there a way to specify that in R - to chnage from 
> the decimal?
I don't have any good answers, but just this:  Arithmetics in any base is
the same.  I believe you just need a way to convert decimal to other bases
and printed out as such.  E.g., 1 + 5 = 6 = 110 in binary.  You just need
something that returns 110 when given 6.  Personally I'd write such a thing
in C because I don't know any better.
 
> (2)
> I also want to extract the digits from a larger number and 
> store them as a vector. I could do it through converting top 
> string, parsing the string and converting back. Is there 
> another way. It would look something like that:
> > a<-1234
> > a
> [1] 1234
> > b<-foo(a)
> > b
>      [,1] [,2] [,3] [,4]
> [1,]    1    2    3    4
Would the following do what you want?
> a <- c(1234, 5678, 90)
> foo <- function(x) strsplit(as.character(x), "")
> foo(a)
[[1]]
[1] "1" "2" "3" "4"

[[2]]
[1] "5" "6" "7" "8"

[[3]]
[1] "9" "0"

HTH,
Andy
 
> Thanks!
> 
> Andrej
> 
> _________
> Andrej Kveder, M.A.
> researcher
> Institute of Medical Sciences SRS SASA; Novi trg 2, SI-1000 
> Ljubljana, Slovenia
> phone: +386 1 47 06 440   fax: +386 1 42 61 493
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list 
> https://www.stat.math.ethz.ch/mailman/listinfo> /r-help
>

Check out:

http://www.wiwi.uni-bielefeld.de/~wolf/software/R-wtools/decodeencode/decodeencode.rev


--- 
Date: Wed, 8 Oct 2003 21:39:50 +0200 
From: Andrej Kveder <andrejk at zrc-sazu.si>
 
 
Dear listers,

I have two questions:
(1)
Is there a way in R to change the base-n of the calculations. I wnat to run
some calculations either in binary (base-2) or base-4. Is there a way to
specify that in R - to chnage from the decimal?

(2)
I also want to extract the digits from a larger number and store them as a
vector.
I could do it through converting top string, parsing the string and
converting back. Is there another way.
It would look something like that:
> a<-1234
> a
[1] 1234
> b<-foo(a)
> b
[,1] [,2] [,3] [,4]
[1,] 1 2 3 4

Thanks!

Andrej

_________
Andrej Kveder, M.A.
researcher
Institute of Medical Sciences SRS SASA; Novi trg 2, SI-1000 Ljubljana,
Slovenia
phone: +386 1 47 06 440 fax: +386 1 42 61 493


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Thanks for the suggestions..

The strsplit function works great for the second question...
I will have to come up with another solution to the first one, since my
problem would definetly involve a lot of calculations and I think that
current methods would cause major computational congestion...
BUt here is the outline of my problem... if anybody has an idea...
 In practice I start with 4 possible correlations: -0.9, -0.1, 0.1, 0.9 and
want to construct all possible 3x3 correaltion matrices with those values.
So I need to do all possible permutations of a given length with
replication. I have a set of 4 distinct values and want to create the
permutations of length 3.
My idea was as folows: specifing the sequence in base-4 form 0 to 333 would
account for all possible combinations.
I checked some of the existing functions which were either recursive and
slow or without replication. I think there was a thread on the list just a
short while ago.
If anybody has a hint to follow, i would be more then glad to try it out...

Thanks again

Andrej

_________
Andrej Kveder, M.A.
researcher
Institute of Medical Sciences SRS SASA; Novi trg 2, SI-1000 Ljubljana,
Slovenia
phone: +386 1 47 06 440   fax: +386 1 42 61 493