[R] R annoyances

Uwe Ligges ligges at statistik.uni-dortmund.de
Thu May 19 17:46:59 CEST 2005


Rod Montgomery wrote:

> Thomas Lumley wrote:
> 
>> On Thu, 19 May 2005, Chalasani, Prasad wrote:
>>
>>> (b) When extracting 2 or more columns of a matrix,
>>>    R returns the result as a matrix, BUT when extracting
>>>    just one column, it returns a vector/array, rather than
>>>    a matrix, so I've to keep doing as.matrix, which is annoying.
>>>
>>>     sub.mtx <- as.matrix(mtx[,1])
>>>
>>>     Of course I could write a suitable function
>>>         cols <- function(mtx,range) as.matrix(mtx[, range])
>>>     but then I lose the syntactic sugar of being able to say "[,1]".
>>
>>
>>
>> This one is actually a FAQ,
>>         mtx[,1,drop=FALSE]
>>
>>     -thomas
>>
> I wonder whether there is, or should be, a way to set FALSE as the default?

First question: No.
Second question: No, because *many* functions do rely on the fact that 
x[,1] returns a vector rather than a matrix.

Uwe Ligges





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