[R] remove NA rows and columns

[Vladimir Eremeev]

Or, these operations can be called in one command:

> testmatrix[-which(apply(testmatrix,1,function(x)all(is.na(x)))),-which(apply(testmatrix,2,function(x)all(is.na(x))))]
     [,1] [,2]
[1,]    1    1
[2,]    2    2
[3,]    1    1
[4,]    2    2
> 



Vladimir Eremeev wrote:
> 
>> testmatrix
>      [,1] [,2] [,3] [,4]
> [1,]   NA   NA   NA   NA
> [2,]   NA    1    1   NA
> [3,]   NA    2    2   NA
> [4,]   NA    1    1   NA
> [5,]   NA    2    2   NA
> [6,]   NA   NA   NA   NA
> 
>> tm1<-testmatrix[,-which(apply(testmatrix,2,function(x)all(is.na(x))))]
>> tm1
>      [,1] [,2]
> [1,]   NA   NA
> [2,]    1    1
> [3,]    2    2
> [4,]    1    1
> [5,]    2    2
> [6,]   NA   NA
> 
>> tm2<-tm1[-which(apply(testmatrix,1,function(x)all(is.na(x)))),]
>> tm2
>      [,1] [,2]
> [1,]    1    1
> [2,]    2    2
> [3,]    1    1
> [4,]    2    2
>  
> 
> Antje wrote:
>> 
>> I guess, it's a rather simple thing but I cannot find a short way to
>> reduce a 
>> matrix, removing all rows and columns having just NA elements.
>> 
>> testmatrix <- matrix(nrow=6, ncol=4)
>> testmatrix[2:5,2:3] <- seq(2)
>> 
>>  > testmatrix
>>       [,1] [,2] [,3] [,4]
>> [1,]   NA   NA   NA   NA
>> [2,]   NA    1    1   NA
>> [3,]   NA    2    2   NA
>> [4,]   NA    1    1   NA
>> [5,]   NA    2    2   NA
>> [6,]   NA   NA   NA   NA
>> 
>> the new matrix should look like this (by the way, I don't "know" which
>> rows and 
>> columns are the one to be deleted...
>> 
>>  > testmatrix
>>       [,1] [,2]
>> [1,]   1    1
>> [2,]   2    2
>> [3,]   1    1
>> [4,]   2    2
>> 
> 
> 

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