[R] rbind ing matrices and resetting column numbers

[David Winsemius]

On Oct 14, 2010, at 10:40 AM, David Winsemius wrote:

>
> On Oct 14, 2010, at 10:31 AM, Maas James Dr (MED) wrote:
>
>> Sorry for the verbose example.  I want to row bind two matrices,  
>> and all works except I want the column labelled "row" to be  
>> sequential in the new matrix, shown as "mat3" here, i.e. needs to  
>> be 1:6 and not 1:3 repeated twice.  Any suggestions?
>
> cbind( row=1:sum(nrow(mat1),nrow(mat2)),
>       rbind(mat1[ ,-1],mat2[ ,-1])
>      )

NOte that using row as a column name could be a bit confusing down the  
line for two reason: a) it's actually a column, and b) "row" is the  
name of a useful function. In fact, that function could be used to  
solve your request using your mat3 constructed below:

 > mat3[ , 1] <- row(mat3)[ , 1]
 > mat3
      row ti counti
[1,]   1  7      9
[2,]   2  8      5
[3,]   3  7      9
[4,]   4  5      3
[5,]   5  6      8
[6,]   6  3      7
>
> -- 
> David.
>>
>> Thanks
>>
>> J
>>
>>> colnm1 <- c("row","ti","counti")
>>> colnm2 <- c("row","tj","countj")
>>> mat1 <- matrix(c(1,7,9,2,8,5,3,7,9),byrow=T,nrow=3)
>>> colnames(mat1) <- colnm1
>>> mat1
>>    row ti counti
>> [1,]   1  7      9
>> [2,]   2  8      5
>> [3,]   3  7      9
>>> mat2 <- matrix(c(1,5,3,2,6,8,3,3,7),byrow=T,nrow=3)
>>> colnames(mat2) <- colnm2
>>> mat2
>>    row tj countj
>> [1,]   1  5      3
>> [2,]   2  6      8
>> [3,]   3  3      7
>>> mat3 <- rbind(mat1,mat2)
>>> mat3
>>    row ti counti
>> [1,]   1  7      9
>> [2,]   2  8      5
>> [3,]   3  7      9
>> [4,]   1  5      3
>> [5,]   2  6      8
>> [6,]   3  3      7
>>
>>
>> ===============================
>> Dr. Jim Maas
>> University of East Anglia
>>
>>
>> 	[[alternative HTML version deleted]]
>>
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.
>
> David Winsemius, MD
> West Hartford, CT
>
> ______________________________________________
> R-help at 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.

David Winsemius, MD
West Hartford, CT