> Gabriel Becker
> on Mon, 15 Mar 2021 15:08:44 -0700 writes:
> Abby,
> Vectors do have an internal mechanism for knowing that they are sorted via
> ALTREP (it was one of 2 core motivating features for 'smart vectors' the
> other being knowledge about presence of NAs).
On 16 March 2021 at 10:50, Martin Maechler wrote:
| I vaguely remember (from Luke's docs/presentation on ALTREP)
| that there are some "missing parts" here.
| One of them the not-existing R level functionality, another may be
| the C code below R's is.unsorted() ... maybe is.unsorted()
| could
Hello R-devel!
The following sequence of commands results in an error message on a
POSIX system:
tab="`echo -ne "\t"`"
LC_ALL=C Rscript -e " $tab 1"
# ARGUMENT '~+~1' __ignored__
Tabs can sneak into the -e argument from indented multi-line arguments
in shell scripts:
Rscript -e '
foo()
Hi all,
I was asked a question about why browser() was behaving a specific way, and
it turned out that it was being called in a script (rather than in a
function).
Putting aside the design considerations that lead to that, the behavior is
actually a bit puzzling, and so far as I have been able to
There are some relatively obvious examples:
unique, which.min/which.max/etc, range/min/max, quantile, aggregate/split
Also, many timeseries, graphics and spline functions are dependent on the order.
In the case of data.frame(s), a boolean flag would probably need to be
extended to allow for multi
Dear all,
Thank you for your consideration on this topic.
I do not have enough knowledge of R internals to join the discussion about
sorting mechanisms. In fact, I did not get how ordering could help for ave as
the output must maintain the order of the input (because ave returns only x and
not
Hi Abby,
I actually have a patch submitted that does this for unique/duplicated
(only numeric cases I think) but it is, as patches from external
contributors go, quite sizable which means it requires a correspondingly
large amount of an R-core member's time and energy to vet and consider. It
is in
Your proposed change (roughly, replacing interaction() by
unique(paste())) slows down ave() considerably when there are long
columns with lots of repeated rows.
I think that interaction(drop=TRUE, ...) can be changed to use less
memory and be faster by making a separate branch for drop=TRUE that
u
Those interested in faster sorting may want to look at the merge sort
implemented in pqR (see pqR-project.org). It's often used as the
default, because it is stable, and does different collations, while
being faster than shell sort (except for small vectors).
Here are examples, with timings, for
