在ggplot2中绘制饼图 [英] Plotting pie charts in ggplot2

问题描述

我想绘制一张适当的饼图。然而，这个网站上的大多数问题都是从 stat = identity 绘制的。如何绘制一个正常的饼图，如图2所示，角度与 cut 的比例成正比？我正在使用ggplot2中的钻石数据框。

  ggplot（data = diamonds，mapping = aes（x = cut，fill = cut））+ 
 geom_bar（width = 1）+ coord_polar（theta =x）
  

图1

解决方案

我们可以先计算每个 cut 组的百分比。我为这个任务使用了 dplyr 软件包。
$ b

  library（ggplot2） 
库（dplyr）
 
＃计算每个组的百分比
 diamonds_summary < -  diamonds％>>％
 group_by（cut）％>％
 summary（Percent = n（）/ nrow（。）* 100）
  

之后，我们可以绘制饼图。 code> scale_y_continuous（breaks = round（cumsum（rev（diamonds_summary $ Percent）），1））是根据累积百分比设置轴标签。 b

  ggplot（data = diamonds_summary，mapping = aes（x =，y = Percent，fill = cut））+ 
 geom_bar（width = 1，stat =identity）+ 
 scale_y_continuous（breaks = round（cumsum（rev（diamonds_summary $ Percent）），1））+ 
 coord_polar（y，start = 0）
  

结果如下。

I want to plot a proper pie chart. However, most of the previous questions on this site were drawn from stat = identity. How can I plot a normal pie chart like graph 2 with the angle proportional to proportion of cut? I am using the diamonds data frame from ggplot2.

ggplot(data = diamonds, mapping = aes(x = cut, fill = cut)) + 
    geom_bar(width = 1) + coord_polar(theta = "x")

Graph 1

ggplot(data = diamonds, mapping = aes(x = cut, y=..prop.., fill = cut)) + 
    geom_bar(width = 1) + coord_polar(theta = "x")

Graph 2

ggplot(data = diamonds, mapping = aes(x = cut, fill = cut)) + 
    geom_bar()

Graph 3

解决方案

We can first calculate the percentage of each cut group. I used the dplyr package for this task.

library(ggplot2)
library(dplyr)

# Calculate the percentage of each group
diamonds_summary <- diamonds %>%
  group_by(cut) %>%
  summarise(Percent = n()/nrow(.) * 100)

After that, we can plot the pie chart. scale_y_continuous(breaks = round(cumsum(rev(diamonds_summary$Percent)), 1)) is to set the axis label based on cumulative percentage.

ggplot(data = diamonds_summary, mapping = aes(x = "", y = Percent, fill = cut)) + 
  geom_bar(width = 1, stat = "identity") + 
  scale_y_continuous(breaks = round(cumsum(rev(diamonds_summary$Percent)), 1)) +
  coord_polar("y", start = 0)

Here is the result.

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