ggplot面对不同规格的ylims

Question

我想在R中创建一个带有六个面板的ggplot数字。前五个面应代表条形图中五个不同的数据子集，最后一个面应代表整个数据。我还希望在前五个方面有一个固定的y轴刻度，但在最后一个方面有不同的刻度。我知道目前无法为ggplot功能（https://github.com/hadley/ggplot2/issues/187）中的每个方面指定单独的ylim，但我想知道我是否可以使用grid和可能gtable做类似的事情包裹，目前我都不熟悉。

以下是我的尝试。我用另一个图中的一个小平面替换了最后一个方面。

library("ggplot2")
library("dplyr")
library("grid")

# create data
set.seed(1)
d1 <- data_frame(
  value = rnorm(3 * 5, mean = 30, sd = 10),
  f = rep(LETTERS[1:3], 5),
  p = rep(paste("Panel", 1:5), each = 3)
)
d2 <- d1 %>%
  mutate(p = "Total") %>%
  rbind(d1)

# make initial figures
plot1 <- ggplot(d2, aes(f, value)) +
  geom_bar(stat = "identity") +
  facet_wrap(~ p) +
  coord_cartesian(ylim = c(0, 50))
plot2 <- ggplot(d2, aes(f, value)) +
  geom_bar(stat = "identity") +
  facet_wrap(~ p, scales = "free_y")

# extract their grobs
g1 <- ggplotGrob(plot1)
g2 <- ggplotGrob(plot2)

# replace the final facet of plot1 with the final facet of plot2
g1[["grobs"]][[7]] <- g2[["grobs"]][[7]]
g1[["grobs"]][[19]] <- g2[["grobs"]][[19]]
g1[["grobs"]][[25]] <- g2[["grobs"]][[25]]

# draw the figure
grid.newpage()
grid.draw(g1)

这就是我得到的。

然而，可以看出，最终小平面的y轴标签与前一小平面重叠。有没有人知道一种避免重叠的方法，例如，通过使最终面更小？

Answer 1

一种方法是从“g2”中提取“总计”图，然后将其插入“g1”，但首先从“g1”中删除“总计”图。但是你会注意到x轴刻度线标签没有在刻面上对齐。

# Load packages
library(ggplot2)
library(dplyr)
library(gtable)
library(grid)

# create data
set.seed(1)
d1 <- data.frame(
  value = rnorm(3 * 5, mean = 30, sd = 10),
  f = rep(LETTERS[1:3], 5),
  p = rep(paste("Panel", 1:5), each = 3)
)
d2 <- d1 %>%
  mutate(p = "Total") %>%
  rbind(d1)

# make initial figures
plot1 <- ggplot(d2, aes(f, value)) +
  geom_bar(stat = "identity") +
  facet_wrap(~ p) +
  coord_cartesian(ylim = c(0, 50))
plot2 <- ggplot(d2, aes(f, value)) +
  geom_bar(stat = "identity") +
  facet_wrap(~ p, scales = "free_y")

# Get the ggplot grobs
g1 <- ggplotGrob(plot1)
g2 <- ggplotGrob(plot2)

# Extract "Total" plot from g2
keep = g2$layout$name %in% c("panel-3-2", "axis-b-3-2", "axis-l-2-3", "strip-t-3-2")
pos = subset(g2$layout, keep, c(t,l,b,r))
g2 = g2[c(min(pos$t):max(pos$b)), c(min(pos$l):max(pos$r))]

# Remove "Total" plot from g1
keep = !g1$layout$name %in% c("panel-3-2", "axis-b-3-2", "strip-t-3-2")
pos = subset(g1$layout, !keep, c(t,l,b,r))
g1$grobs <- g1$grobs[keep]
g1$layout <- g1$layout[keep, ]

# Insert g2 into g1
g1 = gtable_add_grob(g1, g2, t=min(pos$t), b=max(pos$b), l=min(pos$l), r=max(pos$r))

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

另一种方法是像以前一样从“g2”中提取“总计”图，但是将其y轴移动到图的右侧（使用从here借来的代码。（我调整了你的“ plot2“以便刻度线标签在最终图中更好地对齐。）这样，”Total“面板占用的空间与其他面板一样多，因此x轴刻度线标签对齐，但y- “总计”面板的轴向右伸出。

# Make initial figures
plot1 <- ggplot(d2, aes(f, value)) +
  geom_bar(stat = "identity") +
  facet_wrap(~ p) +
  coord_cartesian(ylim = c(0, 50))
plot2 <- ggplot(d2, aes(f, value)) +
  geom_bar(stat = "identity") +
  facet_wrap(~ p, scales = "free_y") +
  theme(axis.text.y = element_text(hjust = 0))    ## For better formatting of labels

# extract their grobs
g1 <- ggplotGrob(plot1)
g2 <- ggplotGrob(plot2)

# Extract "Total" plot from g2
keep = g2$layout$name %in% c("panel-3-2", "axis-b-3-2", "axis-l-2-3", "strip-t-3-2")
pos = subset(g2$layout, keep, c(t,l,b,r))
g2 = g2[c(min(pos$t):max(pos$b)), c(min(pos$l):max(pos$r))]


# Get the position of the panel in the layout
panel <- c(subset(g2$layout, grepl("panel", g2$layout$name), se = t:r))

# Get the row number of the y-axis in the layout
rn <- which(grepl("axis-l", g2$layout$name))

# Extract the axis (tick marks and axis text from the gtable)
axis.grob <- g2$grobs[[rn]]
axisl <- axis.grob$children[[2]]  # Two children - get the second
axisl  # Note: two grobs - tick marks and text

# Reverse the grobs and the widths
axisl$widths <- rev(axisl$widths)
axisl$grobs <- rev(axisl$grobs)

axisl$grobs[[1]]$x <- axisl$grobs[[1]]$x - unit(1, "npc") + unit(2.75, "pt")

axisl$grobs[[2]]$children[[1]]$x = unit(.15, "npc")    

# Remove the column containing the left axis
g2 <- g2[, -(panel$r-1)]

## remove empty panels
keep = !g1$layout$name %in% c("panel-3-2", "axis-b-3-2", "strip-t-3-2")
pos = subset(g1$layout, !keep, c(t,l,b,r))
g1$grobs <- g1$grobs[keep]
g1$layout <- g1$layout[keep, ]

# Insert g2 into g1
g1 = gtable_add_grob(g1, g2, t = min(pos$t), b = max(pos$b), l = min(pos$l), r = max(pos$r))

# Add a new column to g1, and add the revised axisl grob to the new column.
pos = subset(g1$layout, grepl("panel", g1$layout$name), c(t,l,b,r)) # position of bottom right panel
g1 <- gtable_add_cols(g1, axisl$widths, max(pos$r))
g1 <- gtable_add_grob(g1, axisl, t = max(pos$b), l = max(pos$r)+1,  r = max(pos$r)+2)

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