在ggplot2中更改geom_bar的图例键的形状 [英] Change the shape of legend key for geom_bar in ggplot2

问题描述

我试图从geom_bar图形中更改图例关键字的形状。我在网上查看了多个答案，但发现它们在这种情况下不起作用。让我解释一下这个问题：

$ $ $ $ $ $ c $ df1 = data.frame（person = c（person1，person2，person3 ），
variable =variable1，
value = c（0.5,0.3,0.2））

df2 = data.frame（person = c（person1， person2，person3），
variable =variable2，
value = c（-0.3，-0.1，-0.4））
pre>

我试图做一个堆叠的barplot，其中一边是负面的。使用ggplot2我得到：

  library（ggplot2）
 ggplot（）+ geom_bar（data = df1，aes（x = person，y = value，fill = variable），stat =identity）+ 
 geom_bar（data = df2，aes（x = person，y = value，fill = variable），stat =identity） + 
 scale_fill_manual（values = c（steelblue，tomato），breaks = c（variable1，variable2），
 labels = c（Variable 1，Variable 2 ））
  

然后看起来像这样：

现在右边的图例默认显示正方形。有没有办法将它变成一个圆圈？

在线我发现这种方式通常使用的方式是使用

  guides（fill = guide_legend（override.aes = list（shape = 1）））
  

类似的变化。但是，这似乎并不奏效。如果任何人都可以提供帮助，那就太好了，我已经停留了一段时间了。

你可以添加一个图层没有数据的geom_point（仅用于创建图例），并使用 show.legend = FALSE 隐藏栏中不需要的矩形图例：

  df3 = data.frame（person = as.numeric（c（NA，NA）），
 variable = c（variable1，variable2 ），
 value = as.numeric（c（NA，NA）））
 
 ggplot（）+ 
 geom_bar（data = df1，aes（x = person，y =值，fill =变量），stat =identity，show.legend = FALSE）+ 
 geom_bar（data = df2，aes（x = person，y = value，fill = variable），stat =identity ，show.legend = FALSE）+ 
 geom_point（data = df3，aes（x = person，y = value，color = variable），size = 8）+ 
 scale_fill_manual（values = c（steelblue ，tomato），breaks = c（variable1，variable2））+ 
 scale_color_manual（values = c（steelblue，tomato））+ 
 theme（legend.key = element_blank（））
  

I'm trying to change the shape of the legend key from a geom_bar graph. I've looked at multiple answers online but found they didn't work in this case. Let me explain the problem:

df1 = data.frame(person = c("person1", "person2", "person3"),
             variable = "variable1",
             value = c(0.5, 0.3, 0.2))

df2 = data.frame(person = c("person1", "person2", "person3"),
             variable = "variable2",
             value = c(-0.3, -0.1, -0.4))

I'm trying to make a stacked barplot where one side is negative. Using ggplot2 I get:

library(ggplot2)
ggplot() + geom_bar(data = df1, aes(x = person, y = value, fill = variable), stat = "identity") +
  geom_bar(data = df2, aes(x = person, y = value, fill = variable), stat = "identity") +
  scale_fill_manual(values = c("steelblue", "tomato"), breaks = c("variable1","variable2"),
                labels = c("Variable 1", "Variable 2"))

It then looks like this:

Now on the right the legend shows squares by default. Is there a way to change this into a circle for instance?

Online I've found the way this usually works is by using

guides(fill = guide_legend(override.aes = list(shape = 1)))

Or similar variations. However this doesn't seem to work. If anybody can help that would be great, I've been stuck for quite a while now.

解决方案

You could add a layer of geom_point with no data (just to create a legend) and hide the unwanted rectangular legend from the bars using show.legend = FALSE:

df3 = data.frame(person = as.numeric(c(NA, NA)),
                 variable = c("variable1", "variable2"),
                 value = as.numeric(c(NA, NA)))

ggplot() + 
  geom_bar(data = df1, aes(x = person, y = value, fill = variable), stat = "identity", show.legend = FALSE) +
  geom_bar(data = df2, aes(x = person, y = value, fill = variable), stat = "identity", show.legend = FALSE) +
  geom_point(data = df3, aes(x = person, y = value, color = variable), size=8) +
  scale_fill_manual(values = c("steelblue", "tomato"), breaks = c("variable1","variable2")) +
  scale_color_manual(values = c("steelblue", "tomato")) +
  theme(legend.key = element_blank())

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