R help - Feb 2021 - New line in caption with math symbols embedded in expression (paste(

## I am using ggplot and trying to produce a caption containing math symbols. I
need to
## add a second line. I did a fair amount of googling for answers. This one
seemed like
## it would answer my question as it is nearly exactly my problem, except there
is only
## one argument to the paste function. Note that my example is a complete
minimal
## example, just a scatterplot with a line, and the caption content seems to not
have
## anything to do with the plot. That is of course, intentional.
##
##
https://stackoverflow.com/questions/13223846/ggplot2-two-line-label-with-expression

library(ggplot2)
X <- 10*runif(100)
Y <- 2*X + rnorm(100, sd=2)
fit <- lm(Y~X)
Y.p <- predict(fit, newdata=data.frame(X=X))
DAT <- data.frame(X=X)

## without a newline
p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
geom_line(aes(y=Y.p))
p <- p + labs(caption=expression(paste(P,"(",FDP,">",
alpha,") ",
                        "for 'FDR' and 'Auto' FDP control
method, vs '", m,
                        "' at levels of 'eff size' (col) and
'", p[1], "' (row)")))
p <- p + theme(plot.caption = element_text(hjust = 0))

## newline, method 1, just add a new component of paste containing
"\n" somewhere in the middle
p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
geom_line(aes(y=Y.p))
p <- p + labs(caption=expression(paste(P,"(",FDP,">",
alpha,") ",
                        "for 'FDR' and 'Auto' FDP control
method, vs '", m,
                        "' at levels of 'eff size' (col) and
'", p[1], "' (row)",
                        "and \n a new line")))
p <- p + theme(plot.caption = element_text(hjust = 0))

## doesn't work because the newline affects only the last component of
paste. It looks like new line
## works if the line is long enough, but the newline character is being parsed
until the individual
## arguments to paste are parsed for math symbols but prior to pasting the
components together. prior
## to pasting all arguments. I can't imagine why this would be the desired
behavior. When the value of a
## caption argument is expression(paste(s1, s2, s3, ...)) then parsing for a
newline character should
## occur after the components are pasted together, right?

## newline, method 2, enclose paste in another paste and add the new line as the
second argument of the
## outer paste
p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
geom_line(aes(y=Y.p))
p <- p +
labs(caption=expression(paste(paste(P,"(",FDP,">",
alpha,") ",
                        "for 'FDR' and 'Auto' FDP control
method, vs '", m,
                        "' at levels of 'eff size' (col) and
'", p[1], "' (row)"),
                        "and \n a new line")))
p <- p + theme(plot.caption = element_text(hjust = 0))

## which has the same behavior


	[[alternative HTML version deleted]]

Note, from ?plotmath:

"Control characters (e.g., \n) are not interpreted in character strings in
plotmath, unlike normal plotting."

For this reason, as best I can tell, you need to fool with plotmath's
"atop" command or do separate "labs" calls.  This post seems
to confirm
that opinion:

https://stackoverflow.com/questions/29112697/adding-a-newline-in-a-substitute-expression

I certainly would welcome a better alternative.

Cheers,
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, Feb 18, 2021 at 9:37 AM Izmirlian, Grant (NIH/NCI) [E] via R-help <
r-help at r-project.org> wrote:
> ## I am using ggplot and trying to produce a caption containing math
> symbols. I need to
> ## add a second line. I did a fair amount of googling for answers. This
> one seemed like
> ## it would answer my question as it is nearly exactly my problem, except
> there is only
> ## one argument to the paste function. Note that my example is a complete
> minimal
> ## example, just a scatterplot with a line, and the caption content seems
> to not have
> ## anything to do with the plot. That is of course, intentional.
> ##
> ##
>
https://stackoverflow.com/questions/13223846/ggplot2-two-line-label-with-expression
>
> library(ggplot2)
> X <- 10*runif(100)
> Y <- 2*X + rnorm(100, sd=2)
> fit <- lm(Y~X)
> Y.p <- predict(fit, newdata=data.frame(X=X))
> DAT <- data.frame(X=X)
>
> ## without a newline
> p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
> geom_line(aes(y=Y.p))
> p <- p +
labs(caption=expression(paste(P,"(",FDP,">",
alpha,") ",
>                         "for 'FDR' and 'Auto' FDP
control method, vs '", m,
>                         "' at levels of 'eff size' (col)
and '", p[1], "'
> (row)")))
> p <- p + theme(plot.caption = element_text(hjust = 0))
>
> ## newline, method 1, just add a new component of paste containing
"\n"
> somewhere in the middle
> p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
> geom_line(aes(y=Y.p))
> p <- p +
labs(caption=expression(paste(P,"(",FDP,">",
alpha,") ",
>                         "for 'FDR' and 'Auto' FDP
control method, vs '", m,
>                         "' at levels of 'eff size' (col)
and '", p[1], "'
> (row)",
>                         "and \n a new line")))
> p <- p + theme(plot.caption = element_text(hjust = 0))
>
> ## doesn't work because the newline affects only the last component of
> paste. It looks like new line
> ## works if the line is long enough, but the newline character is being
> parsed until the individual
> ## arguments to paste are parsed for math symbols but prior to pasting the
> components together. prior
> ## to pasting all arguments. I can't imagine why this would be the
desired
> behavior. When the value of a
> ## caption argument is expression(paste(s1, s2, s3, ...)) then parsing for
> a newline character should
> ## occur after the components are pasted together, right?
>
> ## newline, method 2, enclose paste in another paste and add the new line
> as the second argument of the
> ## outer paste
> p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
> geom_line(aes(y=Y.p))
> p <- p +
labs(caption=expression(paste(paste(P,"(",FDP,">",
alpha,") ",
>                         "for 'FDR' and 'Auto' FDP
control method, vs '", m,
>                         "' at levels of 'eff size' (col)
and '", p[1], "'
> (row)"),
>                         "and \n a new line")))
> p <- p + theme(plot.caption = element_text(hjust = 0))
>
> ## which has the same behavior
>
>
>         [[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.
>
	[[alternative HTML version deleted]]

Hello,

First of all the plotmath in your code doesn't need paste, expression 
alone will do it.

I am not sure that the following is what you want. I create the caption 
beforehand, in order to make the plotting code simpler.
The asterisks/tildes make less/more space between the text line's elements.


e <- expression(
   atop(
     P * "(" * FDP ~ ">" ~ alpha * ") " ~
       "for 'FDR' and 'Auto' FDP control method, vs
'" *
       m * "' at levels of 'eff size' (col) and '" *
       p[1] * "' (row)" ~ "and",
     "a new line" ~
       bar(x) == sum(frac(x[i], n), i==1, n)
   )
)

p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) + 
geom_line(aes(y=Y.p))
p <- p + labs(caption = e)
p <- p + theme(plot.caption = element_text(hjust = 0))
p


Hope this helps,

Rui Barradas
?s 17:37 de 18/02/21, Izmirlian, Grant (NIH/NCI) [E] via R-help
escreveu:
> ## I am using ggplot and trying to produce a caption containing math
symbols. I need to
> ## add a second line. I did a fair amount of googling for answers. This one
seemed like
> ## it would answer my question as it is nearly exactly my problem, except
there is only
> ## one argument to the paste function. Note that my example is a complete
minimal
> ## example, just a scatterplot with a line, and the caption content seems
to not have
> ## anything to do with the plot. That is of course, intentional.
> ##
> ##
https://stackoverflow.com/questions/13223846/ggplot2-two-line-label-with-expression
> 
> library(ggplot2)
> X <- 10*runif(100)
> Y <- 2*X + rnorm(100, sd=2)
> fit <- lm(Y~X)
> Y.p <- predict(fit, newdata=data.frame(X=X))
> DAT <- data.frame(X=X)
> 
> ## without a newline
> p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
geom_line(aes(y=Y.p))
> p <- p +
labs(caption=expression(paste(P,"(",FDP,">",
alpha,") ",
>                          "for 'FDR' and 'Auto' FDP
control method, vs '", m,
>                          "' at levels of 'eff size' (col)
and '", p[1], "' (row)")))
> p <- p + theme(plot.caption = element_text(hjust = 0))
> 
> ## newline, method 1, just add a new component of paste containing
"\n" somewhere in the middle
> p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
geom_line(aes(y=Y.p))
> p <- p +
labs(caption=expression(paste(P,"(",FDP,">",
alpha,") ",
>                          "for 'FDR' and 'Auto' FDP
control method, vs '", m,
>                          "' at levels of 'eff size' (col)
and '", p[1], "' (row)",
>                          "and \n a new line")))
> p <- p + theme(plot.caption = element_text(hjust = 0))
> 
> ## doesn't work because the newline affects only the last component of
paste. It looks like new line
> ## works if the line is long enough, but the newline character is being
parsed until the individual
> ## arguments to paste are parsed for math symbols but prior to pasting the
components together. prior
> ## to pasting all arguments. I can't imagine why this would be the
desired behavior. When the value of a
> ## caption argument is expression(paste(s1, s2, s3, ...)) then parsing for
a newline character should
> ## occur after the components are pasted together, right?
> 
> ## newline, method 2, enclose paste in another paste and add the new line
as the second argument of the
> ## outer paste
> p <- ggplot(data=DAT, aes(x=X)) + geom_point(aes(y=Y)) +
geom_line(aes(y=Y.p))
> p <- p +
labs(caption=expression(paste(paste(P,"(",FDP,">",
alpha,") ",
>                          "for 'FDR' and 'Auto' FDP
control method, vs '", m,
>                          "' at levels of 'eff size' (col)
and '", p[1], "' (row)"),
>                          "and \n a new line")))
> p <- p + theme(plot.caption = element_text(hjust = 0))
> 
> ## which has the same behavior
> 
> 
> 	[[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.
>