r - 将图例添加到多个 for 循环图的边距

Question

这可能是一个老问题，但我在任何地方都找不到满意的答案。假设我有以下代码：

par(mfrow = c(2,1), mar = c(4,4,1,1), oma=c(2,2,2,2))
stuff <- c("ed", "bla")
cols <- c("red", "blue")
for(i in 1:length(stuff)) {
x <- rnorm(10,3,2)
y <- seq(1,10)
plot(x,y, type = "o", col = cols[i], xlab = paste("stuff about", stuff[i]))}
legend("bottomright", legend = stuff, col = cols, lwd = 1, bty = "n")
par(mfrow=c(1,1))
title(main = "ed & bla", outer = T)
mtext("This is a plot", 3, line=0.5, adj=1.0, cex=1, outer=TRUE)

如何在绘图的底部边缘添加图例？

Answer 1

重新排序绘图请求，以便您在最后一个绘图之后（循环外）但在下一次修改绘图参数之前绘制图例。请注意，仅移动了“legend”命令：

par(mfrow = c(2,1), mar = c(4,4,1,1), oma=c(2,2,2,2))
stuff <- c("ed", "bla")
cols <- c("red", "blue")
for(i in 1:length(stuff)) {
x <- rnorm(10,3,2)
y <- seq(1,10)
plot(x,y, type = "o", col = cols[i], xlab = paste("stuff about", stuff[i]))}
legend("bottomright", legend = stuff, col = cols, lwd = 1, bty = "n")
par(mfrow=c(1,1))
title(main = "ed & bla", outer = T)
mtext("This is a plot", 3, line=0.5, adj=1.0, cex=1, outer=TRUE)

这会将图例放在底部图的右下角。

Answer 2

但你必须手动设置坐标

par(mfrow = c(2,1), mar = c(4,4,1,1), oma=c(2,2,2,2))
stuff <- c("ed", "bla")
cols <- c("red", "blue")
for(i in 1:length(stuff)) {
  x <- rnorm(10,3,2)
  y <- seq(1,10)
  plot(x,y, type = "o", col = cols[i], xlab = paste("stuff about", stuff[i]))}
legend(y=-5, x=5, legend = stuff, col = cols, lwd = 1, bty = "n", xpd=NA)