如何使用ggplot2創建包含百分比標籤的餅圖？

Question

我有一個數據框，並希望在一個特定的列上創建一個餅圖，指出此列中每個級別的百分比。

data <- data.frame(a=c("a1","a1","a2","a3","a1","a2","a3","a4","a2","a1","a5","a4","a3"), 
        b=1:13) 

換句話說，我希望有一個餅圖，表明A1的產生比例，A2，...

此外，我需要在圖表上顯示的百分比。我怎樣才能完成這一切只有ggplot2包？

任何小小的幫助將不勝感激！

Answer 1

嘗試以下操作：

library(dplyr) 
library(ggplot2) 
data <- data.frame(a=c("a1","a1","a2","a3","a1","a2","a3","a4","a2","a1","a5","a4","a3"),b=1:13) 
data <- data %>% 
    group_by(a) %>% 
    count() %>% 
    ungroup() %>% 
    mutate(per=`n`/sum(`n`)) %>% 
    arrange(per) 
data$label <- scales::percent(data$per) 
ggplot(data=data)+ 
    geom_bar(aes(x="", y=per, fill=a), stat="identity", width = 1)+ 
    coord_polar("y", start=0)+ 
    theme_void()+ 
    geom_text(aes(x=1, y = cumsum(per) - per/2, label=label)) 

我還包括餅圖的另一個版本，翻轉圓形切片和標籤的順序（如果這是你的意思）：

ggplot(data=data)+ 
    geom_bar(aes(x="", y=per, fill=a), stat="identity", width = 1)+ 
    coord_polar("y", start=0, direction = -1)+ 
    theme_void()+ 
    geom_text(aes(x=1, y = cumsum(per) - per/2, label=label))