'facet_grid上面的'标签',或者带有facet_wrap的'空格选项'

Question

facet_grid允许我根据y轴上的项目数量(space参数)调整每个构面宽度的大小:

df <- data.frame(label = c("Variable one", rep("Variable two", 2), rep("Variable three", 3)), item = c("A", "B", "C", "D", "E", "F"), value = rnorm(6))
ggplot(df, aes(x = value, y = item)) + 
geom_point() + 
facet_grid(label ~ ., scales = "free_y", space = "free_y") + 
ylab("") + 
theme(strip.text.y = element_text(angle=0))

但是我想在顶部标注facet标签,所以我切换到facet_wrap,并且丢失了space参数(facets具有相同的宽度):

ggplot(df, aes(x = value, y = item)) + 
geom_point() + 
facet_wrap(~ label, scales = "free_y", ncol = 1) + 
ylab("")

是否有可能获得两全其美？

预先感谢您的帮助.

Answer 1

它可以手动完成。所需图中三个面板的高度比约为 1:3:2。三个面板的高度可以通过改变grob来调整：

library(ggplot2)
library(grid)
df <- data.frame(label = c("Variable one", rep("Variable two", 2), rep("Variable three", 3)), item = c("A", "B", "C", "D", "E", "F"), value = rnorm(6))

p1 = ggplot(df, aes(x = value, y = item)) + 
geom_point() + 
facet_wrap(~ label, scales = "free_y", ncol = 1) + 
ylab("")

g1 = ggplotGrob(p1) 

g1$heights[[7]] = unit(1, "null")
g1$heights[[12]] = unit(3, "null")
g1$heights[[17]] = unit(2, "null")

grid.newpage()
grid.draw(g1)

或者，可以将高度设置为与原始图中的高度相同：

p2 = ggplot(df, aes(x = value, y = item)) + 
geom_point() + 
facet_grid(label ~ ., scales = "free_y", space = "free_y") + 
ylab("") + 
theme(strip.text.y = element_text(angle=0))

g2 = ggplotGrob(p2) 

g1$heights[[7]] = g2$heights[[6]]
g1$heights[[12]] = g2$heights[[8]]
g1$heights[[17]] = g2$heights[[10]]

grid.newpage()
grid.draw(g1)

或者，可以在不参考原始图的情况下设置高度。它们可以根据items每个labelin的数量进行设置df。并从@baptiste 的回答中借用一些代码，从与面板对应的布局中选择项目：

# From 'df', get the number of 'items' for each 'label'.
# That is, the number y-breaks in each panel.
library(plyr)
N = dlply(df, .(label), function(x) length(row.names(x)))

# Get the items in the g1 layout corresponding to the panels.
panels1 <- g1$layout$t[grepl("panel", g1$layout$name)]

# Replace the default panel heights with relative heights
g1$heights[panels1] <- unit(N, "null")

## Draw g1
grid.newpage()
grid.draw(g1)

Answer 2

我认为此功能不存在或计划在ggplot2（有关讨论此功能的已关闭问题请参见此处）中实施

但是，该ggforce软件包支持您正在寻找的内容

library(ggplot2)
library(ggforce)
df <- data.frame(label = c("Variable one", rep("Variable two", 2), rep("Variable three", 3)), item = c("A", "B", "C", "D", "E", "F"), value = rnorm(6))
  
ggplot(df, aes(x = value, y = item)) + 
  geom_point() + 
  ggforce::facet_col(facets = vars(label), 
                     scales = "free_y", 
                     space = "free") +
  ylab("") + 
  theme(strip.text.y = element_text(angle=0))

^{由reprex 包(v0.3.0)于 2020 年 6 月 28 日创建}