[R] graphical behavior of a table of numbers

[Duncan Murdoch]

On 29/01/2017 12:05 AM, Jim Lemon wrote:
> Hi Richard,
> I think there may be something amiss in the plot.table function. As
> you note, changing the class of fr to array produces a more sensible
> plot, as does Bert's "as.vector". Yet inside plot.table we find:
>
> plot(x0, unclass(x), ...
>
> and that should produce an array:
>
> class(unclass(fr))
> [1] "array"
>
> The plot.table function looks like it should produce the plot you
> want, but it doesn't. I think (therefore I am probably wrong) that a
> 1D table is handled in the same way as  multiD table rather than being
> squeezed into a vector.

I think the issue is that Axis() is called without removing the class.
Axis.table sets ticks based on the names of the table.

Duncan Murdoch

>
> Jim
>
>
> On Sun, Jan 29, 2017 at 11:19 AM, Bert Gunter <bgunter.4567 at gmail.com> wrote:
>> Rich:
>>
>> Simpler: Just lose the "table" class.
>>
>> plot(as.numeric(names(fr)), as.vector(fr),  type="h",
>>             xlab="Determinant", ylab="Frequency")
>>
>>
>> However, I'm no less puzzled by the "strange" behavior than you.
>>
>> In addition, it's probably worth noting that xyplot in lattice (and no
>> doubt ggplot,too) does not have this problem (as I'm sure you know):
>>
>> xyplot(fr ~ as.numeric(names(fr)),  type="h",
>>             xlab="Determinant", ylab="Frequency")
>>
>>
>> Cheers,
>> Bert
>> Bert Gunter
>>
>> "The trouble with having an open mind is that people keep coming along
>> and sticking things into it."
>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>
>>
>> On Sat, Jan 28, 2017 at 3:03 PM, Richard M. Heiberger <rmh at temple.edu> wrote:
>>> ## This example is from R-intro.pdf page 21 (R-3.3.2)
>>>
>>> d <- outer(0:9, 0:9)
>>> fr <- table(outer(d, d, "-"))
>>> plot(as.numeric(names(fr)), fr, type="h",
>>>             xlab="Determinant", ylab="Frequency")
>>> ## The y-axis tick marks are at c(-21,24,65).
>>> ## This seems to be because class(fr) == "table"
>>>
>>> ## Switching the class to array gives the more appropriate
>>> ## y-axis ticks at seq(0,500,100) .
>>>
>>> fr.array <- fr
>>> class(fr.array) <- "array"
>>> plot(as.numeric(names(fr)), fr.array, type="h",
>>>             xlab="Determinant", ylab="Frequency")
>>>
>>>
>>> ## I have a question and a recommendation.
>>> ## Question:
>>> ## Why are the y-axis ticks for the table defaulted to c(-21,24,65).
>>> ##
>>> ## Recommendation:
>>> ## Changed the example on page 21 to show the ticks at seq(0,500,100)?
>>>
>>> ## Rich
>>>
>>> ______________________________________________
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>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> 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.
>
> ______________________________________________
> 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.
>