如何：更改R中的x轴值？

Question

I have a plot with two y-axes and the corresponding x values run from 1 to 18, in steps of 1. I want to change the x-axis with a scale ranging from 2 to 16 with steps of 1. When I'm trying to alter the scale, the right end of x-scale is empty after 16, as R automatically replaces the old values with the new ones and leaves the empty spaces at the right end open.

par(mar=c(5, 4, 4, 6) + 0.1)
plot(section, c, pch=16, axes=FALSE, ylim=c(-22,-18), xlab=" ", ylab=" ", type="b", col="black", main="BG")
axis(2, ylim=c(-22,-18), col="black", las=1)
mtext(expression(paste(delta^{13}, "C (‰)")),side=2, line=2.5)
box()
par(new=TRUE)
plot(section, n, pch=15, xlab=" ", ylab=" ", ylim=c(10,13), axes=FALSE, type="b", col="red")
axis(4, ylim=c(10,13), col="red", col.axis="red", las=1)
mtext(expression(paste(delta^{15}, "N (‰)")), side=4, col="red", line=4)

axis(1, at=floor(seq(from=2.5, to=15.5, length.out=13)))
axis(1, pretty(range(section), 18))

These last two don't give me the result I'm looking for(can't post my image?).

Any ideas on how to fix this? I would very much appreciate it.

Answer 1

我认为您正在寻找xlim参数。