您将需要fill美学：

library(highcharter)
library(tidyverse)

df1%>% 
  group_by(course_code) %>% 
  hchart("bar", hcaes(x = course_code, y = completion_rate, 
                      fill = Language, group=Language)) %>% 
  hc_add_theme(hc_theme_google()) %>% 
  hc_tooltip(pointFormat = "<b> Completion rate: </b> {point.completion_rate}") %>% 
  hc_title(text = "Course Completion Rates",
           style = list(fontSize = "15px", fontWeight = "bold")) %>% 
  hc_xAxis(title = list(text = "Courses")) %>%
  hc_yAxis(title = list(text = "Completion Rate"))

您应该在hcaes参数之外调用colors，如下所示：

library(highcharter)
library(tidyverse)

df%>% 
  group_by(course_code) %>% 
  hchart("bar", hcaes(x = course_code, y = completion_rate, 
                      group = Language),
         color = c("yellow", "purple")) %>%
  hc_add_theme(hc_theme_google()) %>% 
  hc_tooltip(pointFormat = "<b> Completion rate: </b> {point.completion_rate}") %>% 
  hc_title(text = "Course Completion Rates",
           style = list(fontSize = "15px", fontWeight = "bold")) %>% 
  hc_xAxis(title = list(text = "Courses")) %>%
  hc_yAxis(title = list(text = "Completion Rate"))

输出量：