Altering the margins of a legend in R

问题:

I am very new to R, so I'm struggling here a bit and I haven't found an answer to my problem.

I'm trying to produce a simple bar-chart in R, and I have set my x-axis variable labels to be vertical, using las=2. I then changed the margins for the barplot so that the labels would not overlap the xlab label, using par(mar=c(20,15,5,3)) and par(mgp=c(6,1,0)).

I would like to add a legend to this, but the one I have has adopted the margin dimensions of the graph itself, so that it appears too big and does not fit. I tried using cex but that only affects the text in the legend. Is there anyway for me to change the legend margins (or the graph margins) independently?

Here's what I have coded:

par(mar=c(20,15,5,3))
par(mgp=c(6,1,0))
par(xpd=TRUE)
barplot(
  names.arg=c("Africa", "Central America, South America, Caribbean", 
              "Middle East", "Central and Eastern Europe", 
              "South and East Asia"),
  cex.names=0.8, las=2, t(YLL), 
  ylab="Percentage (%)", ylim=c(0,100), main="", beside=TRUE, 
  col= c("green4", "orange"),xlab="Regions", mar=c(20,15,5,3)
)
legend(
  10, 100, 
  legend=c("Communicable diseases", "Communicable diseases"), 
  fill= c("green4", "orange"), cex=0.7
)

I will really appreciate the help, thanks.

回答1:

You can also use the arguments of legend function: y.intersp, x.intersp and text.width for reduce the size of the legend.

Here an example:

set.seed(55) # Set the seed of R‘s random number generator
x <- 1:10
y <- runif(10, min=0, max=100) # Generating random numbers
z <- runif(10, min=0, max=100) # Generating random numbers
plot(x,y, type="l", ylim=c(0,100), ylab="y and z")
par(new=TRUE)
plot(x,z, type="l", col="red", ylim=c(0,100), ylab=NA, xaxt='n', yaxt='n')
legend("topright", c("y","z"), lty="solid", col=c("black", "red"))

And same code modifiying the legend function:

set.seed(55) # Set the seed of R‘s random number generator
x <- 1:10
y <- runif(10, min=0, max=100) # Generating random numbers
z <- runif(10, min=0, max=100) # Generating random numbers
plot(x,y, type="l", ylim=c(0,100), ylab="y and z")
par(new=TRUE)
plot(x,z, type="l", col="red", ylim=c(0,100), ylab=NA, xaxt='n', yaxt='n')
legend("topright", c("y","z"), lty="solid", col=c("black", "red"), y.intersp=0.5,x.intersp=0.5,text.width=0.1)

回答2:

I don't know if I understood your problem correctly, but maybe you can try x.intersp or y.intersp to modify the spacing in the x and y axis of your legend. For example, you could add x.intersp=0.5 to bring the elements of your legend closer in the x axis.

If this does not work and you provide a screenshot, maybe I could try to help you better.