Re: [R] how do I extract all possible combinations of rows from a column

2014-01-21 Thread arun
Hi,
May be this helps:
library(gtools) 

as.data.frame(t(combinations(5,3,1:5)))
#  V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
#1  1  1  1  1  1  1  2  2  2   3
#2  2  2  2  3  3  4  3  3  4   4
#3  3  4  5  4  5  5  4  5  5   5
A.K.



For a column of data, I need to extract all possible unique 
combinations of 3 rows and combine the results into a data frame (as 
columns). So, for example, if I had a column called test that had five rows 
(the contents of which were the numbers 1:5) all possible 
combinations of 3 rows would be 
1,2,3 
1,2,4 
1,2,5 
1,3,4 
1,3,5 
1,4,5 
2,3,4 
2,4,5 
2,4,5 
3,4,5 

So for this example, R would extract all the combinations shown, and I would 
get a data frame that looked like this 
1     1     1     1     1     1     2     2     2      3       
2     2     2     3     3     4     3     3     4      4   
3     4     5     4     5     5     4     5     5      5     

Note: I am not considering rearrangements of the same three rows
 to be unique. In other words, the combinations 123, 132, 213, 231, 312,
 321 are all the same as far as I am concerned. If it is not possible to
 do it that way, it will still be helpful, but not quite as helpful. 
Thanks for the help!

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Re: [R] how do I extract all possible combinations of rows from a column

2014-01-21 Thread Bert Gunter
... or combn() in utils.

which was the first hit when I googled on finding combinations in R.

So moral: Use search engines before you post.

Cheers,
Bert

Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom.
H. Gilbert Welch




On Tue, Jan 21, 2014 at 12:57 PM, arun smartpink...@yahoo.com wrote:
 Hi,
 May be this helps:
 library(gtools)

 as.data.frame(t(combinations(5,3,1:5)))
 #  V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
 #1  1  1  1  1  1  1  2  2  2   3
 #2  2  2  2  3  3  4  3  3  4   4
 #3  3  4  5  4  5  5  4  5  5   5
 A.K.



 For a column of data, I need to extract all possible unique
 combinations of 3 rows and combine the results into a data frame (as
 columns). So, for example, if I had a column called test that had five rows 
 (the contents of which were the numbers 1:5) all possible
 combinations of 3 rows would be
 1,2,3
 1,2,4
 1,2,5
 1,3,4
 1,3,5
 1,4,5
 2,3,4
 2,4,5
 2,4,5
 3,4,5

 So for this example, R would extract all the combinations shown, and I would 
 get a data frame that looked like this
 1 1 1 1 1 1 2 2 2  3
 2 2 2 3 3 4 3 3 4  4
 3 4 5 4 5 5 4 5 5  5

 Note: I am not considering rearrangements of the same three rows
  to be unique. In other words, the combinations 123, 132, 213, 231, 312,
  321 are all the same as far as I am concerned. If it is not possible to
  do it that way, it will still be helpful, but not quite as helpful.
 Thanks for the help!

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.