将图例添加到由 ggplot 包装的饼图答案

【问题标题】：Adding legend to pie chart that is wrapped by ggplot将图例添加到由 ggplot 包装的饼图
【发布时间】：2020-10-12 18:17:59
【问题描述】：

我对 R 很陌生，需要一些支持来使用 pie 函数。

我需要返回一个 ggplot，所以我用这个包装了 pie 函数。输出是预期的饼图，唯一的问题是，我还想在它旁边有一个图例。

我需要返回一个 ggplot 但不能将它与图例函数结合起来。有人可以提供一些指导吗

【问题讨论】：

标签： r ggplot2 r-markdown legend pie-chart

【解决方案1】：

这和标准的ggplot一样容易，然后你就可以免费获得图例：

library(ggplot2)

slices <- c(10, 12, 4, 5, 8)
countries <- c("US", "Japan", "UK", "Germany", "France")
pct    <- round(slices/sum(slices)*100)
lbls   <- paste(pct, "%", sep="") 
lbl_y  <- 100 - (c(13, 42.5, 62, 73.5, 90))
df     <- data.frame(slices, pct, lbls, countries = factor(countries, levels = countries))

ggplot(df, aes(x = 1, y = pct, fill = countries)) + 
  geom_col(position = "stack", orientation = "x") + 
  geom_text(aes(x = 1, y = lbl_y, label = lbls), col = "white") +
  scale_fill_discrete(breaks = countries) +
  coord_polar(theta = "y", direction = -1) + 
  theme_void()

^{由reprex package (v0.3.0) 于 2020 年 6 月 22 日创建}

【讨论】：

【解决方案2】：

你可以试试这样的：

library(ggplot2)
library(dplyr)
#Data
data <- data.frame(slices = c(10, 12, 4, 5, 8),
                   countries = c("US", "Japan", "UK", "Germany", "France"),
                   stringsAsFactors = F)
#Create variable
data <- data %>% 
  mutate(per=slices/sum(slices)) %>% 
  arrange(desc(countries))
data$label <- scales::percent(data$per)
#Plot
ggplot(data=data)+
  geom_bar(aes(x="", y=per, fill=countries), stat="identity", width = 1)+
  coord_polar("y", start=0)+
  theme_void()+
  geom_text(aes(x=1, y = cumsum(per) - per/2, label=label))+
  ggtitle("pie chart example")

【讨论】：

【解决方案3】：

使用 ggplot2

library(tidyverse)
slices <- c(10, 12, 4, 5, 8)
pct <- round(slices/sum(slices)*100)
lbls <- paste(pct, "%", sep="") 
countries <- c("US", "Japan", "UK", "Germany", "France")

#convert your data to a data frame
df <- data.frame(slices, pct, countries)

#create a stacked bar plot
barPlot <- ggplot(data = df, mapping = aes(x = 1, y = pct, fill = countries)) +
geom_bar(position = 'fill', stat = 'identity')

#change to coordinates to polar
piePlot <- barPlot + 
  coord_polar("y", start = 0) +
  theme_void()+
  theme(legend.position = 'top')
piePlot

【讨论】：