r - ggplot中多个组的密度图

我已经看到example1和How to overlay density plots in R?和Overlapped density plots in ggplot2关于如何制作密度图。我可以使用第二个链接中的代码绘制密度图。但是我想知道如何在ggplot或plotly中制作这样的图形？
我看了所有示例，但无法解决我的问题。
我有一个带有基因表达leukemia data description的玩具数据框，其中的列引用了两组个人

leukemia_big <- read.csv("http://web.stanford.edu/~hastie/CASI_files/DATA/leukemia_big.csv")

df <- data.frame(class= ifelse(grepl("^ALL", colnames(leukemia_big),
                 fixed = FALSE), "ALL", "AML"), row.names = colnames(leukemia_big))

plot(density(as.matrix(leukemia_big[,df$class=="ALL"])),
     lwd=2, col="red")
lines(density(as.matrix(leukemia_big[,df$class=="AML"])),
      lwd=2, col="darkgreen")

最佳答案

Ggplot需要整洁的格式的数据，也称为长格式的数据帧。
以下示例将完成此操作。但是请注意，所提供的数据集按患者类型具有几乎相同的值分布，因此在绘制ALL和AML类型的患者时，曲线重叠并且看不到差异。

library(tidyverse)

leukemia_big %>%
as_data_frame() %>% # Optional, makes df a tibble, which makes debugging easier
gather(key = patient, value = value, 1:72) %>% #transforms a wide df into a tidy or long df
mutate(type = gsub('[.].*$','', patient)) %>% #creates a variable with the type of patient
ggplot(aes(x = value, fill = type)) + geom_density(alpha = 0.5)

在第二个示例中，我将为所有AML类型患者的值变量添加1个单位，以直观地展示重叠问题

leukemia_big %>%
as_data_frame() %>% # Optional, makes df a tibble, which makes debugging easier
gather(key = patient, value = value, 1:72) %>% #transforms a wide df into a tidy or long df
mutate(type = gsub('[.].*$','', patient)) %>% #creates a variable with the type of patient
mutate(value2 = if_else(condition = type == "ALL", true = value, false = value + 1)) %>% # Helps demonstrate the overlapping between both type of patients
ggplot(aes(x = value2, fill = type)) + geom_density(alpha = 0.5)`