Line break in expression()?

Question

I have the following histogram in R:

hist(
  alpha, cex.main=2, cex.axis=1.2, cex.lab=1.2,
  main=expression(
    paste("Histogram of ", hat(mu), ", Bootstrap samples, Allianz")
  )
)

The title is too long, so I want a line break. According to this thread I tried

hist(
  alpha, cex.main=2, cex.axis=1.2, cex.lab=1.2,
  main=expression(
    paste("Histogram of ", hat(mu), ",cat("\n") Bootstrap samples, Allianz")
  )
)

or

hist(
  alpha, cex.main=2, cex.axis=1.2, cex.lab=1.2,
  main=expression(
    paste("Histogram of ",hat(mu), cat("\n"),", Bootstrap samples, Allianz")
  )
)

But both do not work, how can I get a line break in paste()?

IRTFM · Accepted Answer · 2013-08-14T20:39:08.300

50

You can easily use line breaks in regular paste, but this is plotmath paste (actually a different function also with no 'sep' argument) and the (long) ?plotmath page specifically tells you it cannot be done. So what's the work-around? Using the plotmath function atop is one simple option:

expression(atop("Histogram of "*hat(mu), Bootstrap~samples*','~Allianz))

This will break at the comma and center the plotmath expressions. More complicated options are available.

This illustrates plotting to a graphics file. Ironically, the first effort gave me a display that did have your problem with the 'hat' (are those circumflexes?) being cut off and this shows how to increase the margins. The top margin is probably the third number so c(3,3,8,0) might suit you better:

 pdf("test.pdf") ;  par(mar=c(10,10,10,10))
 hist(1:10,cex.main=2,cex.axis=1.2,cex.lab=1.2,
 main=expression(atop("Histogram of "*hat(mu), 
                       Bootstrap~samples * ',' ~Allianz)))
 dev.off() # don't need to restore;  this 'par' only applies to pdf()

edited Aug 14 '13 at 20:39

answered Aug 14 '13 at 16:30

IRTFM

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thanks for your answer, there is only one problem left: The delta and the beta are large in a vertical way, so the hat is out of the range. I.e. the border above is kind of cutting the hat. How can I change this? So move the title down a little bit? – Jen Bohold Aug 14 '13 at 16:37
1

There is an oma argument to `par`::: `opar <- par(oma=c(3,3,3,3))` ....do your plotting ...`par(opar)` Creates extra room around the plot. – IRTFM Aug 14 '13 at 16:40
when I do opar <- par(oma=c(3,3,3,3)) and then par(opar) and then the hist(...) it does not change anything? – Jen Bohold Aug 14 '13 at 16:41
1

You got the order wrong `opar<-par(.)` then `hist(.)`, then `par(opar)`. `par(opar)` is restoring the default settings you "saved to the side" with the first `par` call. – IRTFM Aug 14 '13 at 16:48
Thanks for your answer and I do not want to keep kicking on this point, BUT: This does not help, because the margin increase but the hat is still cutted off! – Jen Bohold Aug 14 '13 at 17:04
1

Different plotting devices I guess. I tested it on my screen device but I hadn't had the problem in the first place. What happens if you print to a pdf device? – IRTFM Aug 14 '13 at 17:07
I don't know how to print to a pdf device? I am just running the code and R Graphics: Device 2 (ACTIVE) opens. No matter if I use fullscreen or not the problem is the same. – Jen Bohold Aug 14 '13 at 17:13
I am just asking, because then your answer is perfect and there is no need using a more complicated version, although the version with bquote is also an excellent solution. – Jen Bohold Aug 14 '13 at 17:14

score 23 · Answer 2 · edited May 23 '17 at 10:31

23

You are going to need to use something else. I was directed to use mtext and bquote when I was stuck on a similar problem.

alpha = rnorm(1e3)
hist(alpha,cex.main=2,cex.axis=1.2,cex.lab=1.2,main=NULL )

title <- list( bquote( paste( "Histogram of " , hat(mu) ) ) ,
               bquote( paste( "Bootstrap samples, Allianz" ) ) )


mtext(do.call(expression, title ),side=3, line = c(1,-1) , cex = 2 )

In the above example, title (thanks to @hadley) can be simplified to

title <- as.list(expression(paste("Histogram of " , hat(mu)), "Bootstrap samples, Allianz"))

enter image description here

edited May 23 '17 at 10:31

Community

1
1

answered Aug 14 '13 at 16:38

Simon O'Hanlon

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1

@JenBohold thanks, alas, I cannot take the credit, I learnt this from agstudy! – Simon O'Hanlon Aug 14 '13 at 16:41
1

As I said... there are more complicated solutions. – IRTFM Aug 14 '13 at 16:42
2

@DWin I personally find this more intuitive than the expression in `atop`. One `bquote` per line. – Simon O'Hanlon Aug 14 '13 at 16:52
@jenbohold that is *entirely* your choice (if you want to accept *any* answer!) – Simon O'Hanlon Aug 14 '13 at 17:08
Don't worry about that. It's not going to insult either of us. – IRTFM Aug 14 '13 at 17:09
2

You can simplify `title` a little to `as.list(expression(paste("Histogram of " , hat(mu)), "Bootstrap samples, Allianz"))` – hadley Aug 14 '13 at 21:05
2

Any similar solution for within a ggplot? – Etienne Low-Décarie Feb 19 '14 at 18:58
If you cannot find another question after searching that answers the ggplot question then you should post another question. (I suspect it's been asked and answered.) – IRTFM Apr 21 '16 at 15:41

Line break in expression()?

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