Question

我想在一个图表中放置两个直方图，但每个直方图都基于不同的列。目前我可以这样做，但position = dodge在这里不起作用。并且没有传说（不同列的颜色不同）。

p <- ggplot(data = temp2.11)
p <- p+ geom_histogram(aes(x = diff84, y=(..count..)/sum(..count..)), 
                       alpha=0.3, fill ="red",binwidth=2,position="dodge")
p <- p+ geom_histogram(aes(x = diff08, y=(..count..)/sum(..count..)), 
                       alpha=0.3,, fill ="green",binwidth=2,position="dodge")

Answer 1

您必须以长格式格式化表格，然后在ggplot中使用长变量作为美学。使用虹膜数据集作为示例......

data(iris)

# your method
library(ggplot2)
ggplot(data = iris) +
  geom_histogram(aes(x = Sepal.Length, y=(..count..)/sum(..count..)), 
                       alpha=0.3, fill ="red",binwidth=2,position="dodge") +
  geom_histogram(aes(x = Sepal.Width, y=(..count..)/sum(..count..)), 
                       alpha=0.3,, fill ="green",binwidth=2,position="dodge")

# long-format method
library(reshape2)
iris2 = melt(iris[,1:2])
ggplot(data = iris2) +
  geom_histogram(aes(x = value, y=(..count..)/sum(..count..), fill=variable), 
                 alpha=0.3, binwidth=2, position="identity")

R ggplot：一个图中的两个直方图（基于两个不同的列）

1 个答案: