binary order combinations

You need to read the help file ?combos, and then use it to do indexing
of your objects, it only knows how to construct the integer combinations
given  a pair (n,p).

url:    www.econ.uiuc.edu/~roger            Roger Koenker
email    rkoenker at uiuc.edu            Department of Economics
vox:     217-333-4558                University of Illinois
fax:       217-244-6678                Champaign, IL 61820



On Sep 5, 2008, at 10:23 AM, Dimitri Liakhovitski wrote:

I am not sure it can do it. Besides, I ran a test of combos from quantreg:

library(quantreg)
H<-1:3
test.combos<-lapply(1:3,function(x)
{combn(H,x)
})

Every time I tried it crashed my R...

:(

Dimitri

On 9/5/08, roger koenker <rkoenker at uiuc.edu> wrote:

Does ?combos in the quantreg package do what you want?


url:    www.econ.uiuc.edu/~roger            Roger Koenker
email    rkoenker at uiuc.edu            Department of Economics
vox:     217-333-4558                University of Illinois
fax:       217-244-6678                Champaign, IL 61820




On Sep 5, 2008, at 9:58 AM, Dimitri Liakhovitski wrote:

Dear all!

I have a vector of names
names<-("V1", "V2", "V3",....., "V15")

I could create all possible combinations of these names (of all
lengths) using R:

combos<-lapply(1:15,function(x)
{combn(names,x)
})

I get a list with all possible combinations of elements of 'names'
that looks like this (just the very beginning of it):

[[1]] - the first element contains all combinations of 1 name
 [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13]

[,14]

[1,] "V1" "V2" "V3" "V4" "V5" "V6" "V7" "V8" "V9" "V10" "V11" "V12"

"V13"

"V14"

 [,15]
[1,] "V15"

[[2]] - the second element contains all possible combinations of 2

names

 [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]  [,10] [,11] [,12] [,13]
[1,] "V1" "V1" "V1" "V1" "V1" "V1" "V1" "V1" "V1"  "V1"  "V1"  "V1"

"V1"

[2,] "V2" "V3" "V4" "V5" "V6" "V7" "V8" "V9" "V10" "V11" "V12" "V13"

"V14"

.
.
.
etc.

My question is: Is there any way to re-arrange all sub-elements of the
above list (i.e., all possible combinations of names such as V1,
V1:V3, V1:V2:V4:V5) in a binary system order. More specifically,
according to this system:
V1=1
V2=2
V3=4
V4=8
V5=16, etc....

So, I'd like those combinations to be arranged in a vector in the
following order:
1. V1 (because V1=1)
2. V2 (because V2=2)
3. V1:V2 (because V1=1 and V2=2 so that 1+2=3)
4. V3 (because V3=4)
5. V1:V3 (because V1=1 and V3=4 so that 1+4=5)
6. V2:V3 (because V2=2 and V3=4 so that 2+4=6)
7. V1:V2:V3 (because V1=1 and V2=2 and V3=4 so that 1+2+4=7)
8. V4 (because V4=8)
etc.

Is it at all possible?
Or maybe there is a way to create the name combinations in such an
order in the first place?

Thank you very much!
Dimitri Liakhovitski