[Rd] problem plotting "ts" in a data.frame

Martyn Plummer plummerm at iarc.fr
Wed Feb 10 16:43:00 CET 2016


On Tue, 2016-02-09 at 16:56 -0600, Spencer Graves wrote:
> Hello:
> 
> 
>        I'm having trouble plotting an object of class "ts" that is in a 
> data.frame.  I can do it with(data.frame, plot(...)) but not with 
> plot(..., data.frame);  see the example below.

The plot function is generic so the actual function call depends on what
arguments you give it: plot(y.ts) calls the plot.ts method from the
stats package, whereas plot(y.ts ~ x) calls the plot.formula method from
the graphics package. Only the plot.formula method has a data argument.

What happens when you call plot(y1~x1, data=XY) is that first
plot.formula is called and then this calls plot.ts with two arguments
(XY$x1 and XY$y1) that are expected to be compatible time series.
However, they are not. In fact x1 is numeric and when coerced to a time
series it has no time points in common with y1 (which starts at time
t=5). Hence the warning about non-intersecting series.

Since non-overlapping series seems to be fatal in this context it might
be a good idea to give an error at this point. Otherwise I think the
function is behaving correctly.

Martyn

>        This work around gets me past this problem.  However, I thought 
> the R Core team might want to know about this if they don't already.
> 
> 
>        Thanks for all your work in making R and CRAN the great tools 
> that they are -- and I apologize for wasting your time if you are 
> already familiar with this.
> 
> 
>        Spencer Graves
> 
> 
>  > y.ts <- ts(2:4, 5)
>  > XY <- data.frame(x1=6:8, y1=y.ts)
>  > plot(y1~x1, XY)
> Error in plot.window(...) : need finite 'xlim' values
> In addition: Warning messages:
> 1: In .cbind.ts(list(...), .makeNamesTs(...), dframe = dframe, union = 
> FALSE) :
>    non-intersecting series
> 2: In min(x) : no non-missing arguments to min; returning Inf
> 3: In max(x) : no non-missing arguments to max; returning -Inf
> 4: In min(x) : no non-missing arguments to min; returning Inf
> 5: In max(x) : no non-missing arguments to max; returning -Inf
>  > plot(y1, XY)
> Error in plot(y1, XY) : object 'y1' not found
>  > with(XY, plot(y1))
>  > sessionInfo()
> R version 3.2.3 (2015-12-10)
> Platform: x86_64-apple-darwin13.4.0 (64-bit)
> Running under: OS X 10.11.2 (El Capitan)
> 
> locale:
> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
> 
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods base
> 
> loaded via a namespace (and not attached):
> [1] tools_3.2.3
> 
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> https://stat.ethz.ch/mailman/listinfo/r-devel

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