Hi all,
Is there a better to way to subset the ROWs (in the sense of NROW) of
an vector, matrix, data frame or array than this?
subset_ROW <- function(x, i) {
nd <- length(dim(x))
if (nd <= 1L) {
x[i]
} else {
dims <- rep(list(quote(expr = )), nd - 1L)
do.call(`[`, c(list(quote(
El vie., 8 jun. 2018 a las 17:46, Hadley Wickham
() escribió:
>
> Hi all,
>
> Is there a better to way to subset the ROWs (in the sense of NROW) of
> an vector, matrix, data frame or array than this?
>
> subset_ROW <- function(x, i) {
> nd <- length(dim(x))
> if (nd <= 1L) {
> x[i]
> } el
Sorry, without remnants from other attempts:
subset_ROW <- function(x, i) {
nd <- length(dim(x))
if (nd <= 1L)
return(x[i])
apply(x, 2:nd, `[`, i, drop=FALSE)
}
El vie., 8 jun. 2018 a las 19:07, Iñaki Úcar () escribió:
>
> El vie., 8 jun. 2018 a las 17:46, Hadley Wickham
> () escribió:
>
There probably should be an abstraction for this. In S4Vectors, we
have extractROWS().
Michael
On Fri, Jun 8, 2018 at 8:45 AM, Hadley Wickham wrote:
> Hi all,
>
> Is there a better to way to subset the ROWs (in the sense of NROW) of
> an vector, matrix, data frame or array than this?
>
> subset_
> On Jun 8, 2018, at 8:45 AM, Hadley Wickham wrote:
>
> Hi all,
>
> Is there a better to way to subset the ROWs (in the sense of NROW) of
> an vector, matrix, data frame or array than this?
You can use TRUE to fill the subscripts for dimensions 2:nd
>
> subset_ROW <- function(x, i) {
> n
I suspect this will have suboptimal performance since the TRUEs will
get recycled. (Maybe there is, or could be, ALTREP, support for
recycling)
Hadley
On Fri, Jun 8, 2018 at 10:16 AM, Berry, Charles wrote:
>
>
>> On Jun 8, 2018, at 8:45 AM, Hadley Wickham wrote:
>>
>> Hi all,
>>
>> Is there a be
On 06/08/2018 10:15 AM, Michael Lawrence wrote:
There probably should be an abstraction for this. In S4Vectors, we
have extractROWS().
FWIW the code in S4Vectors that does what your subset_ROW() does is:
https://github.com/Bioconductor/S4Vectors/blob/04cc9516af986b30445e99fd1337f13321b7b4f6/R
On 06/08/2018 10:32 AM, Hervé Pagès wrote:
On 06/08/2018 10:15 AM, Michael Lawrence wrote:
There probably should be an abstraction for this. In S4Vectors, we
have extractROWS().
FWIW the code in S4Vectors that does what your subset_ROW() does is:
https://urldefense.proofpoint.com/v2/url?u=ht
Also the TRUEs cause problems if some dimensions are 0:
> matrix(raw(0), nrow=5, ncol=0)[1:3 , TRUE]
Error in matrix(raw(0), nrow = 5, ncol = 0)[1:3, TRUE] :
(subscript) logical subscript too long
H.
On 06/08/2018 10:29 AM, Hadley Wickham wrote:
I suspect this will have suboptimal perf
> On Jun 8, 2018, at 10:37 AM, Hervé Pagès wrote:
>
> Also the TRUEs cause problems if some dimensions are 0:
>
> > matrix(raw(0), nrow=5, ncol=0)[1:3 , TRUE]
> Error in matrix(raw(0), nrow = 5, ncol = 0)[1:3, TRUE] :
>(subscript) logical subscript too long
OK. But this is easy enough t
On Fri, Jun 8, 2018 at 11:38 AM, Berry, Charles wrote:
>
>
>> On Jun 8, 2018, at 10:37 AM, Hervé Pagès wrote:
>>
>> Also the TRUEs cause problems if some dimensions are 0:
>>
>> > matrix(raw(0), nrow=5, ncol=0)[1:3 , TRUE]
>> Error in matrix(raw(0), nrow = 5, ncol = 0)[1:3, TRUE] :
>>(subsc
A missing subscript is still preferable to a TRUE though because it
carries the meaning "take it all". A TRUE also achieves this but via
implicit recycling. For example x[ , , ] and x[TRUE, TRUE, TRUE]
achieve the same thing (if length(x) != 0) and are both no-ops but
the subsetting code gets a ch
> On Jun 8, 2018, at 11:52 AM, Hadley Wickham wrote:
>
> On Fri, Jun 8, 2018 at 11:38 AM, Berry, Charles wrote:
>>
>>
>>> On Jun 8, 2018, at 10:37 AM, Hervé Pagès wrote:
>>>
>>> Also the TRUEs cause problems if some dimensions are 0:
>>>
matrix(raw(0), nrow=5, ncol=0)[1:3 , TRUE]
>>>
In the following example, the date class shows Inf as NA
> as_date(Inf, origin = '1970-01-01')
[1] NA
This is misleading as is.na() reports incorrectly
> is.na(as_date(Inf, origin = '1970-01-01'))
[1] FALSE
The correct approach here would probably to have an Inf (and -Inf)
*displayed* rather th
Hmmm, yes, there must be some special case in the C code to avoid
recycling a length-1 logical vector:
dims <- c(4, 4, 4, 1e5)
arr <- array(rnorm(prod(dims)), dims)
dim(arr)
#> [1] 4 4 4 10
i <- c(1, 3)
bench::mark(
arr[i, TRUE, TRUE, TRUE],
arr[i, , , ]
)[c("expression",
Actually, it's sort of the opposite. Everything becomes a sequence of
integers internally, even when the argument is missing. So the same
amount of work is done, basically. ALTREP will let us improve this
sort of thing.
Michael
On Fri, Jun 8, 2018 at 1:49 PM, Hadley Wickham wrote:
> Hmmm, yes, t
The C code for subsetting doesn't need to recycle a logical subscript.
It only needs to walk on it and start again at the beginning of the
vector when it reaches the end. Not exactly the same as detecting the
"take everything along that dimension" situation though.
x[TRUE, TRUE, TRUE] triggers the
> as_date
Error: object 'as_date' not found
Must be from some not-named package...
But don't confuse the format of an object when printed with its underlying
value:
> as.Date(Inf,origin = '1970-01-01')
[1] NA
> str(as.Date(Inf,origin = '1970-01-01'))
Date[1:1], format: NA
> as.numeric(as.Dat
> On Jun 8, 2018, at 1:49 PM, Hadley Wickham wrote:
>
> Hmmm, yes, there must be some special case in the C code to avoid
> recycling a length-1 logical vector:
Here is a version that (I think) handles Herve's issue of arrays having one or
more 0 dimensions.
subset_ROW <-
function(x,i)
On Fri, Jun 8, 2018 at 2:09 PM, Berry, Charles wrote:
>
>
>> On Jun 8, 2018, at 1:49 PM, Hadley Wickham wrote:
>>
>> Hmmm, yes, there must be some special case in the C code to avoid
>> recycling a length-1 logical vector:
>
>
> Here is a version that (I think) handles Herve's issue of arrays hav
On 06/08/2018 02:15 PM, Hadley Wickham wrote:
On Fri, Jun 8, 2018 at 2:09 PM, Berry, Charles wrote:
On Jun 8, 2018, at 1:49 PM, Hadley Wickham wrote:
Hmmm, yes, there must be some special case in the C code to avoid
recycling a length-1 logical vector:
Here is a version that (I think
> On Jun 8, 2018, at 2:15 PM, Hadley Wickham wrote:
>
> On Fri, Jun 8, 2018 at 2:09 PM, Berry, Charles wrote:
>>
>>
>>> On Jun 8, 2018, at 1:49 PM, Hadley Wickham wrote:
>>>
>>> Hmmm, yes, there must be some special case in the C code to avoid
>>> recycling a length-1 logical vector:
>>
>
Indeed. as_date is from lubridate, but the same holds for as.Date.
The output and it's interpretation should be consistent, otherwise it leads
to confusion when programming. I understand that the difference exists
after asking a question on Stack Overflow:
https://stackoverflow.com/q/50766089/91
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