Re: [Rd] ftable <-> data.frame etc {was "justify hard coded in format.ftable"}
That's not the problem. The problem is that if you have
ft <- ftable(UCBAdmissions, row.vars = 3:2)
ft
## Admit Admitted Rejected
## Dept Gender
## AMale 512 313
## Female 89 19
## BMale 353 207
## Female 178
## CMale 120 205
## ... etc ...
then as.data.frame(ft) gives a deconstructed 24x4 data.frame
like this:
as.data.frame(ft)
##Dept GenderAdmit Freq
## 1 A Male Admitted 512
## 2 B Male Admitted 353
## 3 C Male Admitted 120
## 4 D Male Admitted 138
## ... etc ...
which is fine but it does not address the problem here. The
problem here is that we want a a usable data.frame
having columns that correspond to ft. We want this 12x4
data.frame:
##Dept Gender Admitted Rejected
## 1 A Male 512 313
## 2 A Female 89 19
## 3 B Male 353 207
## 4 B Female 178
## ... etc ...
The links I provided already pointed to the code below which
someone posted on SO and solves the problem but I would
have thought this would be easy to do in base R and natural
to provide.
ftable2df <- function(mydata) {
ifelse(class(mydata) == "ftable",
mydata <- mydata, mydata <- ftable(mydata))
dfrows <- rev(expand.grid(rev(attr(mydata, "row.vars"
dfcols <- as.data.frame.matrix(mydata)
names(dfcols) <- do.call(
paste, c(rev(expand.grid(rev(attr(mydata, "col.vars", sep = "_"))
cbind(dfrows, dfcols)
}
ftable2df(ft)
##Dept Gender Admitted Rejected
## 1 A Male 512 313
## 2 A Female 89 19
## 3 B Male 353 207
## 4 B Female 178
## ... etc ...
Fri, May 15, 2020 at 12:25 PM Martin Maechler
wrote:
>
> > Gabor Grothendieck
> > on Thu, 14 May 2020 06:56:06 -0400 writes:
>
> > If you are looking at ftable could you also consider adding
> > a way to convert an ftable into a usable data.frame such as
> > the ftable2df function defined here:
>
> > https://stackoverflow.com/questions/11141406/reshaping-an-array-to-data-frame/11143126#11143126
>
> > and there is an example of using it here:
>
> > https://stackoverflow.com/questions/61333663/manipulating-an-array-into-a-data-frame-in-base-r/61334756#61334756
>
> > Being able to move back and forth between various base class representations
> > seems like something that would be natural to provide.
>
> Sure!
>
> But there is already an as.data.frame() method for "ftable",
> {and I would not want theif(! .. ftable) ftable(x) part anyway.
>
> What I think many useRs / programmeRs very often forget about
> is more-than-2-dimensional arrays {which *are* at the beginning
> of that SO question} and that these are often by far the most
> efficient data structure (rather than the corresponding data frames).
>
> and even less people forget that a "table" in base R is just a
> special case of a 1-D, 2-D, 3-D, array.
> (Semantically a special case: "array" with non-negative integer content
>
> I'd claim that everything you here ("move back and forth between
> ...") is already there in the "ftable" implementation in stats,
> notably in the source file src/library/stats/R/ftable.R
> -> https://svn.r-project.org/R/trunk/src/library/stats/R/ftable.R
>
> The problem may be in
>
> 1) too sparse documentation about the close relations
>"ftable" <-> "array" <-> "table" <-> "data.frame"
>
> 2) people not thinking often enough about more-than-2D-arrays and the
> special corresponding class "table" in R.
>
> To start with one:
>
> > str(UCBAdmissions)
> 'table' num [1:2, 1:2, 1:6] 512 313 89 19 353 207 17 8 120 205 ...
> - attr(*, "dimnames")=List of 3
> ..$ Admit : chr [1:2] "Admitted" "Rejected"
> ..$ Gender: chr [1:2] "Male" "Female"
> ..$ Dept : chr [1:6] "A" "B" "C" "D" ...
> >
>
> and look at the *examples* in the help files and the S3 methods
>
> methods(class = "ftable")
> [1] as.data.frame as.matrix as.table formathead
> print
> [7] tail
> see '?methods' for accessing help and source code
> > methods(class = "table")
> [1] [ aperm as.data.frame Axis coerce
> initialize
> [7] lines plot pointsprint show
> slotsFromS3
> [13] summary tail
> see '?methods' for accessing help and source code
> >
>
> ... need to close now, there's more to be said ...
>
>
>
> > On Thu, May 14, 2020 at 5:32 AM Martin Maechler
> > wrote:
> >>
> >> > SOEIRO Thomas
> >> > on Wed, 13 May 2020 20:27:15 + writes:
> >>
> >> > Dear all,
> >> > I haven't received any feedback so far on my proposal to make
> "justify" argument available in stats:::format.ftable
> >>
> >> > Is this list the appropriate place for this kind of
[Rd] ftable <-> data.frame etc {was "justify hard coded in format.ftable"}
> Gabor Grothendieck
> on Thu, 14 May 2020 06:56:06 -0400 writes:
> If you are looking at ftable could you also consider adding
> a way to convert an ftable into a usable data.frame such as
> the ftable2df function defined here:
> https://stackoverflow.com/questions/11141406/reshaping-an-array-to-data-frame/11143126#11143126
> and there is an example of using it here:
> https://stackoverflow.com/questions/61333663/manipulating-an-array-into-a-data-frame-in-base-r/61334756#61334756
> Being able to move back and forth between various base class representations
> seems like something that would be natural to provide.
Sure!
But there is already an as.data.frame() method for "ftable",
{and I would not want theif(! .. ftable) ftable(x) part anyway.
What I think many useRs / programmeRs very often forget about
is more-than-2-dimensional arrays {which *are* at the beginning
of that SO question} and that these are often by far the most
efficient data structure (rather than the corresponding data frames).
and even less people forget that a "table" in base R is just a
special case of a 1-D, 2-D, 3-D, array.
(Semantically a special case: "array" with non-negative integer content
I'd claim that everything you here ("move back and forth between
...") is already there in the "ftable" implementation in stats,
notably in the source file src/library/stats/R/ftable.R
-> https://svn.r-project.org/R/trunk/src/library/stats/R/ftable.R
The problem may be in
1) too sparse documentation about the close relations
"ftable" <-> "array" <-> "table" <-> "data.frame"
2) people not thinking often enough about more-than-2D-arrays and the
special corresponding class "table" in R.
To start with one:
> str(UCBAdmissions)
'table' num [1:2, 1:2, 1:6] 512 313 89 19 353 207 17 8 120 205 ...
- attr(*, "dimnames")=List of 3
..$ Admit : chr [1:2] "Admitted" "Rejected"
..$ Gender: chr [1:2] "Male" "Female"
..$ Dept : chr [1:6] "A" "B" "C" "D" ...
>
and look at the *examples* in the help files and the S3 methods
methods(class = "ftable")
[1] as.data.frame as.matrix as.table formathead print
[7] tail
see '?methods' for accessing help and source code
> methods(class = "table")
[1] [ aperm as.data.frame Axis coerce
initialize
[7] lines plot pointsprint show
slotsFromS3
[13] summary tail
see '?methods' for accessing help and source code
>
... need to close now, there's more to be said ...
> On Thu, May 14, 2020 at 5:32 AM Martin Maechler
> wrote:
>>
>> > SOEIRO Thomas
>> > on Wed, 13 May 2020 20:27:15 + writes:
>>
>> > Dear all,
>> > I haven't received any feedback so far on my proposal to make
"justify" argument available in stats:::format.ftable
>>
>> > Is this list the appropriate place for this kind of proposal?
>>
>> Yes, it is.. Actually such a post is even a "role model" post
>> for R-devel.
>>
>> > I hope this follow-up to my message won't be taken as rude. Of course
it's not meant to be, but I'm not used to the R mailing lists...
>>
>> well, there could be said much, and many stories told here ... ;-)
>>
>> > Thank you in advance for your comments,
>>
>> > Best,
>> > Thomas
>>
>> The main reasons for "no reaction" (for such nice post) probably
>> are combination of the following
>>
>> - we are busy
>> - if we have time, we think other things are more exciting
>> - we have not used ftable much/at all and are not interested.
>>
>> Even though the first 2 apply to me, I'll have a 2nd look into
>> your post now, and may end up well agreeing with your proposal.
>>
>> Martin Maechler
>> ETH Zurich and R Core team
>>
>>
>>
>>
>> >> Dear all,
>> >>
>> >> justify argument is hard coded in format.ftable:
>> >>
>> >> cbind(apply(LABS, 2L, format, justify = "left"),
>> >> apply(DATA, 2L, format, justify = "right"))
>> >>
>> >> It would be useful to have the possibility to modify the argument
between c("left", "right", "centre", "none") as in format.default.
>> >>
>> >> The lines could be changed to:
>> >>
>> >> if(length(justify) != 2)
>> >> stop("justify must be length 2")
>> >> cbind(apply(LABS, 2L, format, justify = justify[1]),
>> >> apply(DATA, 2L, format, justify = justify[2]))
>> >>
>> >> The argument justify could defaults to c("left", "right") for
backward compatibility.
>> >>
>> >> It could then allow:
>> >> ftab <- ftable(wool + tension ~ breaks, warpbreaks)
>> >> format.ftable(ftab, justify = c("none", "none"))
>> >>
>> >> Best regards,
>> >>
>> >> Thomas
> --
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
