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Therneau, Terry M., Ph.D.

2021-Apr-10 14:12 UTC

[R] evil attributes

I wrote: "I confess to being puzzled WHY the R core has decided on this
definition..."
After just a little more thought let me answer my own question.

a. The as.vector() function is designed to strip off everything extraneous and
leave just
the core.?? (I have a mental image of Jack Webb saying "Just the facts
ma'am"). ? I myself
use it freqently in the test suite for survival, in cases where I'm checking
the corrent
numeric result and don't care about any attached names.

 ?b. is.vector(x) essentially answers the question "does x look like a
result of as.vector?"

Nevertheless I understand Roger's confusion.

-- 
Terry M Therneau, PhD
Department of Quantitative Health Sciences
Mayo Clinic
therneau at mayo.edu

"TERR-ree THUR-noh"


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Viechtbauer, Wolfgang (SP)

2021-Apr-11 18:46 UTC

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[R] evil attributes

The is.vector() thing has also bitten me in the behind on a few occasions. When
I want to check if something is a vector, allow for it to possibly have some
additional attributes (besides names) that would make is.vector() evaluate to
FALSE, but evaluate to FALSE for lists (since is.vector(list(a=1, b=2)) is TRUE
-- which also wasn't what I had initially expected before reading the
documentation), I use:

.is.vector <- function(x)
   is.atomic(x) && !is.matrix(x) && !is.null(x)

This might also work:

.is.vector <- function(x)
   is(x, "vector") && !is.list(x)

I am sure there are all kinds of edge (and probably also not so edge) cases
where these also fail to work properly. Kinda curious if there are better
approaches out there.

Best,
Wolfgang
>-----Original Message-----
>From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Therneau,
Terry
>M., Ph.D. via R-help
>Sent: Saturday, 10 April, 2021 16:12
>To: R-help
>Subject: Re: [R] evil attributes
>
>I wrote: "I confess to being puzzled WHY the R core has decided on this
>definition..."
>After just a little more thought let me answer my own question.
>
>a. The as.vector() function is designed to strip off everything extraneous
and
>leave just
>the core.?? (I have a mental image of Jack Webb saying "Just the facts
>ma'am"). ? I myself
>use it freqently in the test suite for survival, in cases where I'm
checking the
>corrent
>numeric result and don't care about any attached names.
>
> ?b. is.vector(x) essentially answers the question "does x look like a
result of
>as.vector?"
>
>Nevertheless I understand Roger's confusion.
>
>--
>Terry M Therneau, PhD
>Department of Quantitative Health Sciences
>Mayo Clinic
>therneau at mayo.edu
>
>"TERR-ree THUR-noh"

Bill Dunlap

2021-Apr-12 00:44 UTC

head link

[R] evil attributes

Terry wrote
           I confess to being puzzled WHY the R core has decided on this
definition [of vector] ...
I believe that "R core" followed S's definition of
"vector".  From the
beginning (at least when I first saw it in 1981) an S vector was the basic
unit of an S object - it had a type and a length and no more.  This has
little to do with the mathematician's or physicist's notion of a vector.
It is more like what Technopedia (
https://www.techopedia.com/definition/22817/vector-programming) says is a
programmer's notion of a vector:

What Does Vector Mean?
A vector, in programming, is a type of array that is one dimensional.
Vectors are a logical element in programming languages that are used for
storing data. Vectors are similar to arrays but their actual implementation
and operation differs.
Techopedia Explains Vector
Vectors are primarily used within the programming context of most
programming languages and serve as data structure containers. Being a data
structure, vectors are used for storing objects and collections of objects
in an organized structure.
The major difference between and array and a vector is that, unlike typical
arrays, the container size of a vector can be easily increased and
decreased to complement different data storage types. Vectors have a
dynamic structure and provide the ability to assign container size up front
and enable allocation of memory space quickly. Vectors can be thought of as
dynamic arrays.

-Bill

On Sun, Apr 11, 2021 at 8:04 AM Therneau, Terry M., Ph.D. via R-help <
r-help at r-project.org> wrote:
> I wrote: "I confess to being puzzled WHY the R core has decided on
this
> definition..."
> After just a little more thought let me answer my own question.
>
> a. The as.vector() function is designed to strip off everything extraneous
> and leave just
> the core.   (I have a mental image of Jack Webb saying "Just the facts
> ma'am").   I myself
> use it freqently in the test suite for survival, in cases where I'm
> checking the corrent
> numeric result and don't care about any attached names.
>
>   b. is.vector(x) essentially answers the question "does x look like a
> result of as.vector?"
>
> Nevertheless I understand Roger's confusion.
>
> --
> Terry M Therneau, PhD
> Department of Quantitative Health Sciences
> Mayo Clinic
> therneau at mayo.edu
>
> "TERR-ree THUR-noh"
>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
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R help - Apr 2021 - evil attributes

[R] evil attributes

[R] evil attributes

[R] evil attributes