r - 将不同数据的 abline 添加到 xyplot 面板

Question

使用 R 中的 lattice，我使用 factors 选项绘制了一个 xyplot。现在我想为每个图添加一个水平 abline，但是在另一个数据框中。我怎样才能在他们对应的面板中得到这些行？

EDIT - example:

MyData <- data.frame(
  v1 = 1:50,
  v2 = rnorm(50,20,5),
  v3 = c(rep("one", 10), rep("two", 10),  rep("three", 10), rep("four", 10), rep("five", 10)))


require(latticeExtra)

xyplot(
  v1 ~ v2 | v3,
  data = MyData,
  layout = c(5, 1),
  scales = list(
    x = list(relation="free"),
    y = list(relation="same")
  )
)

# Now the horizontal lines I want to draw
lineData <- c(30,30,20,20,40) 
# each for one column, from left to right; another option would be
lineData <- data.frame(
  v3 = c("one","two","three","four","five"),
  height = c(30,30,20,20,40)
)

# I know this will not work for each correspondent panel, separately...
abline(h = lineData)

Answer 1

下面是我将如何确保值匹配

lineData <- data.frame(
  v3 = c("one","two","three","four","five"),
  height = c(30,30,20,20,40)
)

xyplot(
  v1 ~ v2 | v3,
  data = MyData,
  layout = c(5, 1),
  scales = list(
    x = list(relation="free"),
    y = list(relation="same")
  ),
  panel = function(x, ...) {
      level <- dimnames(trellis.last.object())[["v3"]][packet.number()]
      panel.xyplot(x, ...);
      panel.abline(h = lineData$height[lineData$v3==level])
  }
)

这产生