R中的标签对数刻度显示

Question

在绘制组织图，散点图和其他图（轴的比例缩放为R的对数）时，如何使用诸如10 ^ -1 10 ^ 0 10 ^ 1 10 ^ 2 10 ^ 3之类的标签代替显示的轴只是-1、0、1、2、3等。应该在命令中添加哪些参数，例如hist（），plot（）等？

Answer 1

Apart from the solution of ggplot2 (see gsk3's comment), I would like to add that this happens automatically in plot() as well when using the correct arguments, eg :

x <- 1:10
y <- exp(1:10)
plot(x,y,log="y")

You can use the parameter log="x" for the X axis, or log="xy" for both.

If you want to format the numbers, or you have the data in log format, you can do a workaround using axis(). Some interesting functions :

• axTicks(x) gives you the location of the ticks on the X-axis (x=1) or Y-axis (x=2)
• bquote() converts expressions to language, but can replace a variable with its value. More information on bquote() in the question Latex and variables in plot label in R? .
• as.expression() makes the language object coming from bquote() an expression. This allows axis() to do the formatting as explained in ?plotmath . It can't do so with language objects.

An example for nice formatting :

x <- y <- 1:10
plot(x,y,yaxt="n")
aty <- axTicks(2)
labels <- sapply(aty,function(i)
            as.expression(bquote(10^ .(i)))
          )
axis(2,at=aty,labels=labels)

Which gives

Answer 2

Here is a different way to draw this type of axis:

plot(NA, xlim=c(0,10), ylim=c(1, 10^4), xlab="x", ylab="y", log="y", yaxt="n")
at.y <- outer(1:9, 10^(0:4))
lab.y <- ifelse(log10(at.y) %% 1 == 0, at.y, NA)
axis(2, at=at.y, labels=lab.y, las=1)

EDIT: This is also solved in latticeExtra with scale.components

Answer 3

In ggplot2 you just can add a

... + 
scale_x_log10() + 
scale_y_log10(limits = c(1e-4,1), breaks=c(1e-4,1e-3,1e-2,0.1,1)) + ...

to scale your axis, Label them and add custom breaks.