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)
There are likely additional tweaks that could be made, as Nick may require.
Regards,
Marc
> On Jun 6, 2019, at 5:53 PM, Duncan Murdoch <murdoch.dun...@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_schwa...@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.4...@gmail.com> wrote:
>>>>
>>>> Yes, plot(z,y,..)
>>>>
>>>> Bert
>>>>
>>>> On Thu, Jun 6, 2019 at 9:21 AM Nick Wray <nicholas.w...@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.4...@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@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_schwa...@me.com> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> On Jun 6, 2019, at 11:19 AM, Nick Wray via R-help <
>>>>> r-help@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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