[R] calling plot

[Bert Gunter]

Oh, yes certainly. But I thought the point was to avoid "cheating"
with with() or assuming that the "x" argument was a formula.

Yes, my "smarter" solution doesn't work  -- my error. I still think
there must be a small tweak to fix it, but I haven't figured it out
yet. AFAICS, my earlier "stupid" solution does work as originally
intended with no "cheating" :

> plotxy <- function(x,data = NULL,...){
+    mcall <- match.call()
+    if(inherits(x,"formula"))enc <- environment(x)
+     else enc <- parent.frame()
+    if(!is.null(data)){
+         env <- data
+         mcall <- mcall[-match("data",names(mcall))]
+    } else env <- NULL
+    mcall[[1]] <- plot.default
+    eval(mcall,envir=env,enclos=enc)
+ }
>
>
>
>  XY <- data.frame(x1=1:3, y1=4:6)
>  plotxy(y1~x1, XY, xlim=c(0, max(x1)))

The problem with your original approach I believe is that the
evaluator wants to evaluate xlim before it passes it on to your plot
call. By default, it evaluates it in the parent frame where there is
no x1 -- ergo the error (I would appreciate correction if this is
wrong).  If you look at the code for plot.default() and then
grDevices:: xy.coords, you'll see how the call is parsed and evaluated
in the appropriate environment.  My code above is trying to do the
same thing, though I may still have holes.

Cheers,
Bert




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 Tue, Feb 9, 2016 at 8:33 AM, Spencer Graves
<spencer.graves at effectivedefense.org> wrote:
>
>
> On 2/9/2016 9:51 AM, Bert Gunter wrote:
>>
>> Spencer, et. al.:
>>
>> As I suspected, my previous "solution" was pretty stupid. Here is, I
>> think, the "right" way to
>>   go about it:
>>
>>   plotxy <- function(x,...){
>>     mcall <- match.call(expand.dots=FALSE)
>>     mcall[[1]]<- plot.default
>>     eval(mcall)
>>   }
>
>
>
> Hi, Bert, et al.:  I couldn't get that to work, either:
>
>
>> XY <- data.frame(x1=1:3, y1=4:6)
>> plotxy(y1~x1, XY, xlim=c(0, max(x1)))
>
>  Error in eval(expr, envir, enclos) : object 'y1' not found
>
>
>       However, my original function inside "with" worked, but Bert's
> suggestion didn't:
>
>
>> plot.sg <- function(x, ...){
> + plot(x, ...)
> + }
>> with(XY, plot.sg(y1~x1, xlim=c(0, max(x1))))
>> # worked, but "plotxy" with match.call didn't:
>> with(XY, plotxy(y1~x1, xlim=c(0, max(x1))))
>
>  Error in eval(expr, envir, enclos) : object 'y1' not found
>
>> 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
>
>
>       I don't understand this, but "with" is acceptable for my current
> needs.
>
>
>       Thanks again to Bert & Jeff.
>
>
>       Spencer Graves
>>
>>
>> Best,
>> 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 Mon, Feb 8, 2016 at 8:10 PM, Spencer Graves
>> <spencer.graves at effectivedefense.org> wrote:
>>>
>>> Hi, Jeff et al.:
>>>
>>>
>>> On 2/8/2016 9:52 PM, Jeff Newmiller wrote:
>>>>
>>>> plotxy(y1~x1, XY, xlim=c(0, max(XY$x1)))
>>>
>>>
>>>         Yes, Thanks.
>>>
>>>
>>>         Is there a way to do this from within "plotxy", so I can call
>>> "plotxy" as I call "plot"?
>>>
>>>
>>>         Thanks,
>>>         Spencer
>>>
>>>
>>>> --
>>>> Sent from my phone. Please excuse my brevity.
>>>>
>>>> On February 8, 2016 7:17:57 PM PST, Spencer Graves
>>>> <spencer.graves at effectivedefense.org> wrote:
>>>>
>>>>      I'm getting an interesting error:
>>>>
>>>>
>>>>          plotxy <- function(x, ...){
>>>>
>>>>      +   plot(x, ...)
>>>>      + }
>>>>
>>>>          XY <- data.frame(x1=1:3, y1=4:6) plotxy(y1~x1, XY, xlim=c(0,
>>>>          max(x1)))
>>>>
>>>>         Show Traceback
>>>>
>>>>         Rerun with Debug
>>>>         Error in eval(expr, envir, enclos) : object 'x1' not found
>>>>
>>>>
>>>>              The following work:
>>>>
>>>>
>>>>      plotxy(y1~x1, XY)
>>>>      plot(y1~x1, XY, xlim=c(0, max(x1)))
>>>>
>>>>
>>>>              Within "plotxy", R can't find "x1" to compute "xlim".  Is
>>>> there a
>>>>      way I can make x1 available to xlim?
>>>>
>>>>
>>>>              Thanks,
>>>>              Spencer
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>>      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
>>>> guidehttp://www.R-project.org/posting-guide.html
>>>>      and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>          [[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.
>
>