r - 重叠堆积密度图

Question

我正在尝试使用 R 的本机绘图命令来实现与此类似的绘图。

我可以通过下面的代码得到类似的东西，但是，我希望密度多边形重叠。谁能建议一种方法来做到这一点？

data = lapply(1:5, function(x) density(rnorm(100, mean = x)))

par(mfrow=c(5,1))
for(i in 1:length(data)){
  plot(data[[i]], xaxt='n', yaxt='n', main='', xlim=c(-2, 8), xlab='', ylab='', bty='n', lwd=1)
  polygon(data[[i]], col=rgb(0,0,0,.4), border=NA)
  abline(h=0, lwd=0.5)
}

输出：

Answer 1

我会做如下的事情。我在同一个图中绘制了密度，但在 y 值上添加了一个整数。为了使它们重叠，我乘以一个常数因子fac。

# Create your toy data
data <- lapply(1:5, function(x) density(rnorm(100, mean = x)))

fac <- 5  # A factor to make the densities overlap

# We make a empty plot
plot(1, type = "n", xlim = c(-3, 10), ylim = c(1, length(data) + 2),
     axes = FALSE, xlab = "", ylab = "")  

# Add each density, shifted by i and scaled by fac
for(i in 1:length(data)){
  lines(  data[[i]]$x, fac*data[[i]]$y + i)
  polygon(data[[i]]$x, fac*data[[i]]$y + i, col = rgb(0, 0, 0, 0.4), border = NA)
  abline(h = i, lwd = 0.5)
}

Answer 2

（注意：此内容之前已编辑到问题中，由@by0 撰写。）

感谢@AEBilgrau，我很快就把这个功能很好地组合在一起。fac注意：您需要根据您的数据使用该因素。

stacked.density <- function(data, fac = 3, xlim, col = 'black', 
                            alpha = 0.4, show.xaxis = T, 
                            xlab = '', ylab = ''){
  xvals = unlist(lapply(data, function(d) d$x))
  if(missing(xlim)) xlim=c(min(xvals), max(xvals))

  col = sapply(col, col2alpha, alpha)
  if(length(col) == 1) col = rep(col, length(data))

  plot(1, type = "n", xlim = xlim, ylim = c(1,length(data) + 2),
       yaxt='n', bty='n', xaxt=ifelse(show.xaxis, 'l', 'n'), xlab = xlab, ylab = ylab)

  z = length(data):1
  for(i in 1:length(data)){
    d = data[[ z[i] ]]
    lines(d$x, fac*d$y + i, lwd=1)
    polygon(d$x, fac*d$y+ i, col=col[i], border=NA)
    abline(h = i, lwd=0.5)
  }
}

data <- lapply(1:5, function(x) density(rnorm(100, mean = x)))
stacked.density(data, col=c('red', 'purple', 'blue', 'green', 'yellow'), alpha=0.3, show.xaxis=T)

输出：