间隔绘制x轴值

Question

I will like to plot some data, with the x-axis data plotted at intervals

X:

50.0000
100.5467
689.7431
1559.8025
1000.9365
10.9095

Y:

-0.0596123270783229
 0.644158691971081
-0.433854284204926
-0.365746109442603
 0.566685929975495
 0.398462720589891 

Function:

plotM<- function( dat, m ) {
  plot(data$X, data$Y,
       log="x", pch=20, cex=0.7,
       col = ifelse( data$Y < m, "red", "black" ), 
       xlab = "Y", ylab = expression(Log[2]~Fold~Change))
}

Function call:

plotM(dat, .05) 

How can I plot the data with the following sequence in x-axis:

10, 100, 1000, 2000

Thanks

Answer 1

You need to create a plot with no axes then add them manually.

Using some example data

x = 10^(0:3)
y = 0:3

We plot x and y and specify no axis are to be plotted:

plot(x, y, log="x", axes=FALSE, frame=TRUE)

Then add on the x and y axis manually

## See ?axis for more details
axis(1, 10^(0:3), 10^(0:3))
axis(2)

Alternatively, we can be a bit more fancy with the axis labels to get

axis(1, 10^(0:3),  c(expression(10^0), 
                     expression(10^1), 
                     expression(10^2), 
                     expression(10^3)))

to get

Answer 2

Try this... I have used ggplot2, much used graphical package of R.

It will create x axis on log scale using ggplot..

ggplot(data = data) + geom_line(aes(x = x, y = y)) + scale_x_log10()

This is how results will look like...