[R] plotmath and logical operators?

[Bert Gunter]

This is clumsy and probably subject to considerable improvement, but does
it work for you:

left <- quote(x >= 3)
right <- quote(y <= 3) ## these can be anything

## the plot:
plot(1)
eval(substitute(mtext(expression(paste(left, " & ",right))), list(left =
left, right = right)))

## Expression evaluation
eval(substitute(with(df,left & right), list(left = left, right = right)))

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 Mon, Aug 20, 2018 at 2:00 PM MacQueen, Don via R-help <
r-help using r-project.org> wrote:

> I would like to use plotmath to annotate a plot with an expression that
> includes a logical operator.
>
> ## works well
> tmp <- expression(x >= 3)
> plot(1)
> mtext(tmp)
>
> ## not so well
> tmp <- expression(x >= 3 &  y <= 3)
> plot(1)
> mtext(tmp)
>
> Although the text that's displayed makes sense, it won't be obvious to my
> non-mathematical audience.
>
> I'd appreciate suggestions.
>
>
> I've found a work-around that gets the annotation to look right
>   tmpw <- expression(paste( x >= 3, " & ", y <= 3) )
>   plot(1)
>   mtext(tmpw)
>
>
> But it breaks my original purpose, illustrated by this example:
>
> df <- data.frame(x=1:5, y=1:5)
> tmp <- expression(x >= 3 & y <= 3)
> tmpw <- expression(paste( x >= 3, " & ", y <= 3) )
> with(df, eval(tmp))
> [1] FALSE FALSE  TRUE FALSE FALSE
> with(df, eval(tmpw))
> [1] "FALSE  &  TRUE" "FALSE  &  TRUE" "TRUE  &  TRUE"  "TRUE  &  FALSE"
> "TRUE  &  FALSE"
>
> Thanks
> -Don
>
> --
> Don MacQueen
> Lawrence Livermore National Laboratory
> 7000 East Ave., L-627
> Livermore, CA 94550
> 925-423-1062
> Lab cell 925-724-7509
>
>
>
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