[R] Pasting R code lines into labels
Nick Wray
n|cho|@@@wr@y @end|ng |rom nt|wor|d@com
Fri Jun 7 15:33:56 CEST 2019
Wow! I hadn't meant to set off such an email flurry... Tbh all I wanted to do was to label some plots for my own recording and notes so Bert's idea was more than adequate. On the other hand it's instructive to venture further into the R-universe in such distinguished company...
Nick
> On 07 June 2019 at 14:25 Martin Maechler <maechler using stat.math.ethz.ch> wrote:
>
>
> >>>>> Marc Schwartz via R-help
> >>>>> on Fri, 7 Jun 2019 09:07:21 -0400 writes:
>
> > Hi, Ok, some additional tweaks.
>
> > Relative to Bert's pointing out the aesthetic issues,
> > certainly, those are attributes that can be adjusted as
> > Nick may require. I was focused more on the primary
> > issue. Using "..." is an easy way to pass additional
> > parameters to plot.default() as Bert indicated.
>
> > To Duncan's point, here is a modification of my original
> > function to allow for the passing of an expression, rather
> > than pre-creating a function and passing that:
>
> > plotFx <- function(x, expr, ...) {
> > expr <- substitute(expr)
> > y <- eval(expr)
> > plot(x, y, main = paste0("Plot of y = ", deparse(expr)), ...)
> > }
>
> > plotFx(1:10, x^2)
> > plotFx(1:10, cos(x))
> > plotFx(1:10, exp(x) + 1)
>
> well yes....
>
> Ross/Robert/?? had invented the curve() function to do
> something like that even before R got a version number !!
> and we (it may have been me) had added a
>
> plot.function() method for plot() which behaved very
> similarly, also long before R version 1.0.x
>
> Are you sure you don't want to use one of
>
> plot(<function>, ...)
> or
> curve(..)
>
> instead of what you are doing now?
> Look at the result of
>
> example(plot.function)
>
> and
>
> example(curve)
>
> to get a bit of a show-off of these ..
>
> > There are likely additional tweaks that could be made, as Nick may require.
>
> > Regards,
> > Marc
>
> ... tweaks which may already be available in curve() / plot.function().
> At the time, I had invested many many man hours to tweak them to
> become as versatile as seemed feasible ...
>
> Martin Maechler
> ETH Zurich and R Core
>
>
>
> >> On Jun 6, 2019, at 5:53 PM, Duncan Murdoch <murdoch.duncan using gmail.com> wrote:
> >>
> >> These look like very fragile suggestions. Allow x^2 to be an argument (named expr, for example) to plotFx, don't force a user to write a function in a very particular way. Then use deparse(substitute(expr)) in the title.
> >>
> >> Duncan Murdoch
> >>
> >> On 06/06/2019 4:33 p.m., Bert Gunter wrote:
> >>> Well, if you want to do it this way, note that as written, the y axis
> >>> default label isn't "nice," and you should anyway allow for additional
> >>> graphical arguments (either way). Also, slightly better I think is to use
> >>> the built-in access function, body():
> >>> plotFx <- function(x, fun, ...) {
> >>> plot(x, fun(x), main = paste0("Plot of y = ", deparse(body(fun))), ...)
> >>> }
> >>> x <- 1:10
> >>> f <- function(x) x^2
> >>> plotFx(x, f, col = "red", ylab = "y")
> >>> 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 Thu, Jun 6, 2019 at 12:19 PM Marc Schwartz <marc_schwartz using me.com> wrote:
> >>>> Hi,
> >>>>
> >>>> Sorry for the misfire on the first attempt.
> >>>>
> >>>> After seeing the clarifications, I thought about a possible way to do
> >>>> this, perhaps a little more simply, while encapsulating the plotting in a
> >>>> function:
> >>>>
> >>>> plotFx <- function(x, fun) {
> >>>> plot(x, fun(x), main = paste0("Plot of y = ", deparse(fun)[2]))
> >>>> }
> >>>>
> >>>> So let's say that you have:
> >>>>
> >>>> x <- 1:10
> >>>>
> >>>> f <- function(x) x^2
> >>>> plotFx(x, f)
> >>>>
> >>>> f <- function(x) cos(x)
> >>>> plotFx(x, f)
> >>>>
> >>>> f <- function(x) exp(x) + 1
> >>>> plotFx(x, f)
> >>>>
> >>>>
> >>>> In the case of the first function, you get:
> >>>>
> >>>>> deparse(f)
> >>>> [1] "function (x) " "x^2"
> >>>>
> >>>> for the second:
> >>>>
> >>>>> deparse(f)
> >>>> [1] "function (x) " "cos(x)"
> >>>>
> >>>> and for the third:
> >>>>
> >>>>> deparse(f)
> >>>> [1] "function (x) " "exp(x) + 1"
> >>>>
> >>>>
> >>>> Thus, the "deparse(fun)[2]" snippet within the internal paste0() function
> >>>> call, gets you the second, textual part of the function body, which can
> >>>> then be passed as a character vector to the titles or other labels as
> >>>> needed.
> >>>>
> >>>> A potential gotcha that I would envision, is that the default width in the
> >>>> character vector resulting from deparse() is 60. Thus, by default the
> >>>> function body would broken up into multiple character segments, no longer
> >>>> than approximately 60 characters each. Thus, if you envision that you might
> >>>> end up with very long formulae on x, you may need to adjust the
> >>>> width.cutoff argument in the deparse() call, and likely need to do some
> >>>> additional formatting of the labels in the plot as apropos.
> >>>>
> >>>> There may be other functional nuances that I am missing here, but this may
> >>>> be a suitable approach.
> >>>>
> >>>> Regards,
> >>>>
> >>>> Marc
> >>>>
> >>>>
> >>>>> On Jun 6, 2019, at 2:11 PM, Bert Gunter <bgunter.4567 using gmail.com> wrote:
> >>>>>
> >>>>> Yes, plot(z,y,..)
> >>>>>
> >>>>> Bert
> >>>>>
> >>>>> On Thu, Jun 6, 2019 at 9:21 AM Nick Wray <nicholas.wray using ntlworld.com>
> >>>> wrote:
> >>>>>
> >>>>> Thanks Bert, that is exactly what I wanted. I think that you meant
> >>>>> plot(z,y... in the last line?
> >>>>>
> >>>>> Nick
> >>>>>
> >>>>> On 06 June 2019 at 17:13 Bert Gunter <bgunter.4567 using gmail.com> wrote:
> >>>>>
> >>>>> ... and if you wanted too streamline the process, something like the
> >>>>> following could be encapsulated in a function:
> >>>>>
> >>>>> fun <- quote(exp(x))
> >>>>> z <- 1:9
> >>>>> y <- eval(fun,list(x = z) )
> >>>>> plot(x, y, main = paste("Plot of y =", deparse(fun)))
> >>>>>
> >>>>> Further details can be found in the "Computing on the Language" section
> >>>> of
> >>>>> the "R Language Reference" manual or from suitable tutorials on the web.
> >>>>>
> >>>>> 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 Thu, Jun 6, 2019 at 8:55 AM Nick Wray via R-help <
> >>>> r-help using r-project.org>
> >>>>> wrote:
> >>>>>
> >>>>> Thanks but that's not quite what I meant
> >>>>> I am trying out different functions and they don't necessarily vary in a
> >>>>> regular way (like say all being powers of x where it'd be simple to just
> >>>>> have a vector for the powers you want)
> >>>>> So I might have
> >>>>> y<-x^2
> >>>>> y<-cos(x)
> >>>>> y<-exp(x+1)
> >>>>> What I am after is a way of running these functions and then calling
> >>>> each
> >>>>> one into the labelling for the appropriate graph as I plot it. So then
> >>>> I
> >>>>> would have something like
> >>>>> mainlab<-paste("Plot of ",function in question)
> >>>>> ...? Thanks Nick
> >>>>>
> >>>>>>> On 06 June 2019 at 16:40 Marc Schwartz < marc_schwartz using me.com> wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>> On Jun 6, 2019, at 11:19 AM, Nick Wray via R-help <
> >>>>> r-help using r-project.org> wrote:
> >>>>>>>>
> >>>>>>>> Is there any way of taking a line of r code (eg y<-x^2) and pasting
> >>>>> that line of code, as is, into a label, so that for example I could then
> >>>>> have a plot label "Plot of y<-x^2"?
> >>>>>>>>
> >>>>>>>> Thanks Nick Wray
> >>>>>>>
> >>>>>>>
> >>>>>>> Hi,
> >>>>>>>
> >>>>>>> See ?plotmath
> >>>>>>>
> >>>>>>> An example:
> >>>>>>>
> >>>>>>> x <- 1:10
> >>>>>>> y <- x^2
> >>>>>>>
> >>>>>>> plot(x, y, main = expression(paste("Plot of ", y %<-% x^2)))
> >>>>>>>
> >>>>>>>
> >>>>>>> There are other incantations and examples on the help page above.
> >>>>>>>
> >>>>>>> Regards,
> >>>>>>>
> >>>>>>> Marc Schwartz
> >>>>>>>
>
> > ______________________________________________
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> > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
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