R中xy曲线图内的阴影

Question

我有类似以下数据:

X <- 1:20
B <- c(1,4,6,3,1, 4, 5,8,8,6,3,2,1, 1,5,7,8,6,4,2)
C <- B + 4
myd <- data.frame (X, B, C)

我希望在曲线内用不同的颜色着色.请注意x中的边界颜色填充

region 1 = 1 to 6
 region 2 =  6 to 16
 region 3 =  16 to 20 

Answer 1

只需演示1:6部分:

R> plot(X, B, type="l", col="blue", xlim=c(0, 25), ylim=c(0, 15))
R> par(new=TRUE)
R> plot(X, C, type="l", col="red", xlim=c(0, 25), ylim=c(0, 15))
R> polygon(c(1:6, 6:1), c(B[1:6], C[6:1]), col="purple")