legend(x, y, legend, fill, col = "black", lty, lwd = 1, pch, bty = "o", bg = par("bg"), cex = 1, xjust = 0, yjust = 1, x.intersp = NULL, y.intersp = NULL, text.width = NULL, merge = FALSE)
x
| the x location of the legend. |
y
| the y location of the legend. |
legend
|
a vector of text values or an expression
of length >= 1 to appear in the legend.
|
fill
| if specified, this argument will cause boxes filled with the specified colors to appear beside the legend text. |
col
| the color of points or lines appearing in the legend. |
lty,lwd
| the line types and widths for lines appearing in the legend. One of these two must be specified for line drawing. |
pch
| the plotting symbols appearing in the legend, either as vector of 1-character strings, or one (multi character) string. Must be specified for symbol drawing. |
bty
| the type of box to be drawn around the legend. |
bg
| the background color for the legend box. |
cex
|
character expansion factor relative to current
par("cex") .
|
xjust
| how the legend is to be justified relative to the legend x location. A value of 0 means left justified, 0.5 means centered and 1 means right justified. |
yjust
|
the same as xjust for the legend y location.
|
x.intersp
| character interspacing factor for horizontal (x) spacing. |
y.intersp
|
the same as x.intersp for vertical (y) line
distances.
|
text.width
|
the width of the legend text in x ("user" )
coordinates.
Defaults to the proper value computed by strwidth(legend) .
|
merge
|
logical; if TRUE , ``merge'' points and lines but
not filled boxes.
|
locator
can be used in place of the x
and y
arguments.x.intersp
and y.intersp
are
computed from Cx <- cex * par('cex')
.
``Attribute'' arguments such as col
, lty
, pch
,
etc, are recycled if necessary.
plot
, barplot
which uses legend()
, and
text
for more examples of math expressions.# Run the example in `?matplot' or the following: matplot(c(1,8), c(0,4.5), type = "n", xlab = "Length", ylab = "Width", main = "Petal and Sepal Dimensions in Iris Blossoms") leg.txt <- c(" Setosa Petals", " Setosa Sepals", "Versicolor Petals", "Versicolor Sepals") y.leg <- c( 4, 3, 2.2, 1.5, .9) cexv <- c( 1, .8, .6, .4, .25) * if(.Device=="Postscript") 1.2 else 1 for (i in seq(cexv)) legend(1, y.leg[i], leg.txt, pch = "sSvV", col = c(1, 3), cex = cexv[i]) # `merge = TRUE' for merging lines & points: x <- seq(-pi, pi, len = 65) plot(x, sin(x), type = "l", ylim = c(-1.2, 1.8), col = 3, lty = 2) points(x, cos(x), pch = 3, col = 4) lines(x, tan(x), type = "b", lty = 1, pch = 4, col = 6) title("legend(..... lty = c(2, -1, 1), pch = c(-1,3,4), merge = TRUE)", cex.main = 1.1) legend(-1, 1.9, c("sin", "cos", "tan"), col = c(3,4,6), lty = c(2, -1, 1), pch = c(-1, 3, 4), merge = TRUE, bg='gray90') ##--- log scaled Examples ------------------------------ leg.txt <- c("a one", "a two") par(mfrow = c(2,2)) for(ll in c("","x","y","xy")) { plot(2:10, log=ll, main=paste("log = '",ll,"'", sep="")) abline(1,1) lines(2:3,3:4, col=2) # points(2,2, col=3) # rect(2,3,3,2, col=4) text(c(3,3),2:3, c("rect(2,3,3,2, col=4)", "text(c(3,3),2:3,\"c(rect(...)\")"), adj = c(0,.3)) legend(list(x=2,y=8), legend = leg.txt, col=2:3, pch=1:2, lty=1, merge=T)#, trace=T) } par(mfrow=c(1,1)) ##-- Math expressions: ------------------------------ plot(x, sin(x), type="l", col = 2,xlab=expression(phi),ylab=expression(f(phi))) abline(h=-1:1, v=pi/2*(-6:6), col="gray90") lines(x, cos(x), col = 3, lty = 2) ex.cs1 <- expression(plain(sin) * phi, paste("cos", phi))# 2 ways legend(-3, .9, ex.cs1, lty=1:2, col=2:3) x <- rexp(100, rate = .5) hist(x, main = "Mean and Median of a Skewed Distribution") abline(v = mean(x), col=2, lty=2, lwd=2) abline(v = median(x), col=3, lty=3, lwd=2) ex12 <- expression(bar(x) == sum(over(x[i], n), i==1, n), hat(x) == median(x[i], i==1,n)) legend(4.1, 30, ex12, col = 2:3, lty=2:3, lwd=2)