# [R] binary order combinations

roger koenker rkoenker at uiuc.edu
Fri Sep 5 17:53:33 CEST 2008

```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
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>
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