[R] Plot title with numeric variables

[RMan54]

This works for the original posted question:

n<-5
title <- bquote(bold(paste("Figure ", .(n), ": Plot ", C[max], " versus
CrCl")))
plot(1, main=title)
 
However, my problem is that I want to define the text before the value of n
is known.
The idea is that the title is defined ahead, passed to a function that makes
many plots, and n is incremented for each plot.

One way to accomplish this would be to have the constant part of the title
defined ahead:

fff <- bquote(paste("Plot ", C[max], " versus CrCl"))

Unfortunanely, I need to use bquote() or expression() in order to get the
subscript correctly (subscript in the wordprocessing sense = text placed a
little bit lower than normal).

And then add to this the changing part at the time the plot is made (when
the value of n is correct).

The changing part is:

ccc <- bquote(paste("Figure ", .(n), ":"))

Unfortunatley, I need to use bquote() or substitute() here to replace n with
it's numeric value. This can actually be done simplier: paste("Figure", n,
":")

I just don't know how to concatenate both fff and ccc to create the title.

I am wondering whether it is possible to construct variables or strings that
contain the text plus the special charaters for subscript (square brackets)
and the code for replacement of n by its numeric value, and then evaluate
the combination as part of a substitute() function.

As a try that does not work:

fff <- expression(paste("Plot ",C[max]," versus CrCl"))     # Need
expression() for subscript text
n<-5
ccc <- bquote(paste("Figure ", .(n), ":")) 
# Need bquote() for replacement of n; can be done with substitute() also, or
simple: paste("Figure", n, ":")

title <- paste(fff, ccc)  ##### Does not work; produces strange results in
plot title #####
plot(1, main=title)

LARGER PEROBLEM:
My larger problem is to construct a number of plots in sets with the same
title per set (fixed part per set) but with the title number incremented
with 1 starting with 1 (variable part). I wanted to define the fixed part of
the title in the main loop but have the figure counter rolling in a function
just before each plot is constructed at which time the figure number is
known.

Very ackward, but this works as the main loop:

numSetsOfPlots <- 1:2
numPlotsPerSet <- 1:3
n <- 0
for (setNo in numSetsOfPlots) {
    for (plotInSetNo in numPlotsPerSet) {
      n <- n + 1
      if (setNo == 1) myTitle <-  bquote(paste("Figure ", .(n), ": ",
C[max]))
      if (setNo == 2) myTitle <-  bquote(paste("Figure ", .(n), ": ", AUC))
      plot(1, main=myTitle) # Will be a call to a more complex plot function
      readline('Press Enter to proceed...')
    }
}

At this point, I can NOT separate a Figure counter from the fixed part of
the title. Both have to be combined in the same main loop. The need for the
subscript for which a PlotMath function is needed causes this problem.

--------------------------
Rene Braeckman, PhD (RMan54)
Irvine, CA 


RMan54 wrote:
> 
> I am trying to create a plot title in R with substitution by a numeric
> variable (Figure number N) within the text which is bold and has a
> subcripted part as well. Here is what I have:
> 
> title <- expression(bold(paste("Figure ", N, ": Plot ", C[max], " versus
> CrCL")))
> 
> plot(1, main="") # Simple plot for testing
> N <- 5
> mtext(title, line=3, font=2, cex=1.25)
> 
> I have the bold part and the subscripted text worked out but how do I
> replace the text "N" in the title by its numeric value (5 in this
> example)? I tried all kinds of stuff with substitute, etc. but can't
> figure it out. 
> 
> The last 3 lines are actually from a function with title as argument. N is
> internal to the function and changes.
> 
> Any help is much appreciated. Thanks.
> Rene
> 
> 

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