在ggplot中绘制具有负面和正面的累积直方图？

Question

R version 3.1.1 (2014-07-10) Platform: i386-w64-mingw32/i386 (32-bit)

我正在使用ggplot2制作直方图。目的是在一个图中组合负面和正面的累积直方图。很容易，我可以分别为负面和正面绘制直方图，但只要我将它们组合起来就会变得一团糟。

示例数据：

df <- structure(list(NEG = c(-42.962, -1.86, -13.275, -56.188, -2.25, 
-12.199, -3.953, -13.309, -4.512, -11.461, -19.813, -54.311, 
-59.934, -7.045, -14.44, -40.829, -143.034, -233.009, -70.72, 
-5.578), POS = c(180.328, 290.809, 156.894, 31.414, 629.74, 590.672, 
268.89, 69.618, 415.007, 138.444, 10.139, 20.565, 106.027, 69.129, 
19.809, 8.22, 53.711, 36.035, 11.694, 12.705)), .Names = c("NEG", 
"POS"), row.names = c(NA, 20L), class = "data.frame")

积极方面的代码确实有效：

ggplot(df)+ 
      geom_histogram(aes(x= POS, y=rev(cumsum(rev(..count..)))/4),binwidth=1)

负面代码也有效：

ggplot(df)+ 
      geom_histogram(aes(x= NEG, y=cumsum(..count..)/4),binwidth=1)

但是将这两层结合起来会产生一团糟：

ggplot(df)+ 
      geom_histogram(aes(x= POS, y=rev(cumsum(rev(..count..)))/4),binwidth=1)+
      geom_histogram(aes(x= NEG, y=cumsum(..count..)/4),binwidth=1)

我希望你能帮助我！

非常感谢！

Answer 1

问题在于，对于两个图层，累计和在整个x轴上计算。

ggplot(df)+ 
  geom_histogram(aes(x= POS, y=ifelse(x>=0, 
                                      rev(cumsum(rev(..count..)))/4, 
                                      0)),
                 binwidth = 1)+ 
  geom_histogram(aes(x= NEG, y=ifelse(x<=0,
                                      cumsum(..count..)/4,
                                      0)),
                 binwidth = 1)