如何使用 ggplot2 在不同方面为 2x2 排列添加水平线？

Question

我有一个数据库，它是按刻面绘制和分隔的。第一行（行a）的面需要0.5处的水平线，而第二行（行b）的面需要1处的线。我已经部分实现了以下目标this example。但是，0.5 和 1 处的水平线出现在所有面中。

library(ggplot2)

#Data
values <- c(0.4, 0.6, 0.9, 1.1)
Column <- c("UW", "LW", "UW", "LW")
Row <- c("a", "a", "b", "b")
DF <- data.frame(Row, Column, values)
DF$Column <- factor(DF$Column,
                 levels = c("UW", "LW"))
DF$Row <- factor(DF$Row,
                 levels = c("a", "b"))

#Auxiliar DF
Target <- c("a", "b")
Lines <- c(0.5, 1)
Lines_in_plot <- data.frame(Target, Lines)
Lines_in_plot$Target <- factor(Lines_in_plot$Target)

#Plot
ggplot(data = DF, aes(y = values)) +
  geom_bar() +
  facet_grid(Row~Column,
             scales = "free") +
  geom_hline(data = Lines_in_plot,
             yintercept = Lines,
             linetype = "dashed",
             color = "red")

此 MWE 运行但显示以下警告消息：

geom_hline(): Ignoring `data` because `yintercept` was provided.

Answer 1

为了在特定面板中显示拦截，您需要将 facet_grid 中引用的 Row 作为 Lines_in_plot 中的变量提供。您还需要将 yintercept 放在 aes 中，以便 ggplot 知道引用 Lines_in_plot 数据 yintercept.

...
#Auxiliar DF
Row <- c("a", "b")
Lines <- c(0.5, 1)
Lines_in_plot <- data.frame(Row, Lines)
Lines_in_plot$Row <- factor(Lines_in_plot$Target)

#Plot
ggplot(data = DF, aes(y = values)) +
  geom_bar() +
  facet_grid(Row~Column,
             scales = "free") +
  geom_hline(data = Lines_in_plot,
             aes(yintercept = Lines),
             linetype = "dashed",
             color = "red")

Answer 2

这是您的解决方案：


library(ggplot2)

#Data
values <- c(0.4, 0.6, 0.9, 1.1)
Column <- c("UW", "LW", "UW", "LW")
Row <- c("a", "a", "b", "b")
DF <- data.frame(Row, Column, values)
DF$Column <- factor(DF$Column,
                 levels = c("UW", "LW"))
DF$Row <- factor(DF$Row,
                 levels = c("a", "b"))

#Auxiliar DF
Row <- c("a", "b")
Lines <- c(0.5, 1)
Lines_in_plot <- data.frame(Row, Lines)
Lines_in_plot$Row <- factor(Lines_in_plot$Row)

#Plot
ggplot(data = DF, aes(y = values)) +
  geom_bar() +
  facet_grid(Row~Column,
             scales = "free") +
  geom_hline(data = Lines_in_plot,
             aes(yintercept = Lines),
             linetype = "dashed",
             color = "red")

两个变化：

将y截距移入美学
将目标重命名为 Row 以匹配 Facet，以便它知道如何处理它们

如何使用 ggplot2 在不同方面为 2x2 排列添加水平线？

How to add horizontal lines in different facets for 2x2 arrangements using ggplot2?

r

facet

ggplot2

geom-hline