具有動態返回值的 Ggplot scale_fill_manual

Question

我有一個 dataframe，其中包含多列因子類型（有 5 個級別：深綠色、綠色、橙色、黃色、灰色），盡管每個包含不同的值，如下面的屏幕截圖所示。

我試圖定義一個 function 來制作一個條形圖，其中包含由所選列中包含的值手動設置的圖例 colors，如下所示

library(tidyverse)
make_graph <- function(df, col){
  data = select(df, group, col)
  G = data$group
  C = data$col
  tbl = prop.table(table(G, C))
  DF = data.frame(tbl) %>% filter(freq != 0)
ggplot(data, aes(x=G,y=Freq, fill=C)) +
 geom_bar(stat="identity", position="dodge") + theme_minimal() +
 scale_fill_manual(values=c(?????), labels=c(?????))  # needs to be automatically filled with the values contained in the selected column

我的問題是：如何根據提供給 function make_graph的列動態設置參數values和labels ？ 例如，如果我執行此make_graph(df, 'col_2')它將顯示 3 個條形圖，其中 colors 為深綠色、綠色和橙色，圖例值為“很好”、“好”和“好”

PS：以下是 akrun 提供的代碼的結果，其中圖例值與 colors 不一致（例如，深綠色應標記為“好”而不是“可怕”）

Answer 1

library(dplyr)
library(ggplot2)
make_graph <- function(df, col){
 keyval <- setNames(c("great", "good", "ok", "poor", "terrible"), 
      c("dark green", "green", "orange", "yellow", "grey"))
 fill_m <- keyval[df[[col]]]
df %>%
   select(group, all_of(col)) %>%
   count(across(everything())) %>%
   mutate(prop = n/sum(n)) %>%
   filter(n != 0) %>%
   ggplot(aes(x = group, y = n, fill = .data[[col]])) +
     geom_bar(stat= "identity", position = "dodge") + 
     theme_minimal() +
     scale_fill_manual(values = names(fill_m), labels = fill_m)



}

-測試

make_graph(df1, "col_2")

數據

df1 <- structure(list(group = structure(c(1L, 2L, 1L, 2L), levels = c("1", 
"2"), class = "factor"), col_1 = c("dark green", "dark green", 
"dark green", "dark green"), col_2 = c("dark green", "green", 
"orange", "orange"), col_3 = c("green", "yellow", "dark green", 
"grey"), col_4 = c("grey", "dark green", "orange", "yellow"), 
    col_5 = c("dark green", "grey", "grey", "grey")), row.names = c(NA, 
-4L), class = c("tbl_df", "tbl", "data.frame"))