[R] Pasting R code lines into labels

[Bert Gunter]

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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