ggplot一组直方图与直方图作为subplots

Question

我有三个网站收集的数据，其中每个这些数据收集几个主题的几次。

这里的数据是如何模样：

set.seed(1) 
df <- data.frame(site = c(rep("AA",1000),rep("BB",500),rep("CC",750)), 
       y = c(rnorm(1000,1,2),runif(500,1,3),rgamma(750,shape=1))) 

#add subjects - using a function that randomly generates 
#a number of subjects that adds up to their total at that site 

site_a_subjects <- diff(c(0, sort(20*sample(19)), 1000)) 
site_b_subjects <- diff(c(0, sort(30*sample(9)), 500)) 
site_c_subjects <- diff(c(0, sort(40*sample(4)), 750)) 

#add these subjects 
df$site_subjects <- c(unlist(sapply(1:20, function(x) rep(letters[x], site_a_subjects[x]))), 
        unlist(sapply(1:10, function(x) rep(letters[x], site_b_subjects[x]))), 
        unlist(sapply(1:5, function(x) rep(letters[x], site_c_subjects[x])))) 

我想绘制的y每个每个站点的直方图。 这ggplot2简单的线条实现了轻松：

ggplot(df, aes(x=y)) + geom_histogram(colour="black", fill="white") + facet_grid(. ~ site) 

不过，我想另外在每个站点直方图绘制，一个插曲是在该网站每个受试者观察数的计数的直方图。 喜欢的东西加入：

hist(table(df$site_subjects[which(df$site == "AA")])) 
hist(table(df$site_subjects[which(df$site == "BB")])) 
hist(table(df$site_subjects[which(df$site == "CC")])) 

分别

三个网站直方图。

任何想法如何做到这一点？

我不知道是否可以调整annotation_custom来达到这个目的吗？

此代码将工作，但前提是：

ggplotGrob(ggplot(df, aes(x=site_subjects)) + geom_bar() + theme_bw(base_size=9)) 

命令可以接受ggplot的list一个对象或类似的东西。

这里是'几乎;解决方案： 首先要弄清楚什么是所有方面中的最大栏高度直方图

ymax <- max(sapply(unique(df$site), function(x) max(hist(df$y[which(df$site == x)],plot=FALSE)$counts))) 

然后：

main.plot <- ggplot(df, aes(x=y)) + geom_histogram(colour="black", fill="gray") + facet_grid(~site) + scale_y_continuous(limits=c(0,1.2*ymax)) 
main.plot.info <- ggplot_build(main.plot) 
xmin <- min(main.plot.info$data[[1]]$x[which(main.plot.info$data[[1]]$PANEL == 1)]) 
xmax <- max(main.plot.info$data[[1]]$x[which(main.plot.info$data[[1]]$PANEL == 1)]) 
main.plot <- main.plot + annotation_custom(grob = grid::roundrectGrob(),xmin = xmin, xmax = xmax, ymin=ymax, ymax=1.2*ymax) 
sub.plot <- ggplotGrob(ggplot(df, aes(x=site_subjects)) + geom_bar() + theme_bw(base_size=9)) 
combined.plot <- main.plot + annotation_custom(grob = sub.plot, xmin = xmin, xmax = xmax, ymin=ymax, ymax=1.2*ymax) 

，其结果是：

Answer 1

一种方式做，这是创建主图，然后通过在要插入图的每个位置创建视口来添加每个嵌入图。我们使用grid包中的函数来执行这些操作。这里有一个例子：

library(grid) 

# Function to draw the inset plots 
    pp = function(var) { 
    grid.draw(
     ggplotGrob(
     ggplot(df[df$site==var,], aes(site_subjects)) + 
      geom_bar() + 
      theme_bw(base_size=9) 
    ) 
    ) 
    } 

# Function to place the viewports on the main graph 
my_vp = function(x) { 
    viewport(x=x, y=.8, width=0.25, height=0.2) 
} 

# Main plot 
ggplot(df, aes(x=y)) + geom_histogram(colour="black", fill="white") + 
    facet_grid(. ~ site) + 
    scale_y_continuous(limits=c(0,400)) 

# Draw each inset plot in a separate viewport 
vp = my_vp(0.22) 
pushViewport(vp) 
pp("AA") 
popViewport() 

vp = my_vp(0.52) 
pushViewport(vp) 
pp("BB") 
popViewport() 

vp = my_vp(0.84) 
pushViewport(vp) 
pp("CC") 

Answer 2

这里的东西合理：

ymax <- max(sapply(unique(df$site), function(x) max(hist(df$y[which(df$site == x)],plot=FALSE)$counts))) 
sites <- unique(df$site) 
plot.list <- sapply(sites, function(s) { 
    main.plot = ggplot(df[which(df$site == s),], aes(x=y)) + geom_histogram(colour="black", fill="gray") + scale_y_continuous(limits=c(0,1.5*ymax)) 
    main.plot.info = ggplot_build(main.plot) 
    xmin = min(main.plot.info$data[[1]]$x[which(main.plot.info$data[[1]]$PANEL == 1)]) 
    xmax = max(main.plot.info$data[[1]]$x[which(main.plot.info$data[[1]]$PANEL == 1)]) 
    sub.plot = ggplotGrob(ggplot(df[which(df$site == s),], aes(x=site_subjects)) + geom_bar() + theme_bw(base_size=9)) 
    return(ggplotGrob(main.plot + annotation_custom(grob = sub.plot, xmin = xmin, xmax = xmax, ymin=0.8*ymax, ymax=1.2*ymax)))}) 

grid.arrange(grobs=plot.list, ncol=3)