R 如何制作已排序的几何图形条（）ggplot

我的数据帧称为：

d3

变量名称：

课程名称、id、注册总数、总容量

我做到了：

d3a <- head(d3[order(d3$total_capacity, decreasing = T),], 15)
d3.plottable <- d3a[, c(1,3,4)]
d3.plottable <- melt(d3.plottable, id.vars = "course_name")

library(ggplot2)

g <- ggplot(d3.plottable, aes(x = course_name, y = value))
g + geom_bar(aes(fill = variable), position = position_dodge(), stat = "identity") + 
  coord_flip() + theme(legend.position = "top")
g <- g + labs(x = "Course Name")
g <- g+ labs(y = "Number of Students")
g

---

d3a这里是一个重新定义
因子
级别顺序的示例

注意，由于您没有提供示例数据，我将模拟一些数据

# Sample data
set.seed(2017);
df <- cbind.data.frame(
    course_name = rep(LETTERS[1:6], each = 2),
    value = sample(300, 12),
    variable = rep(c("total_enrolled", "total_capacity"), length.out = 12)
);

# Relevel factor levels, ordered by subset(df, variable == "total_enrolled")$value
df$course_name <- factor(
    df$course_name,
    levels = as.character(subset(df, variable == "total_enrolled")$course_name[order(subset(df, variable == "total_enrolled")$value)]));

# Plot
require(ggplot2);
g <- ggplot(df, aes(x = course_name, y = value))
g <- g + geom_bar(aes(fill = variable), position = position_dodge(), stat = "identity");
g <- g + coord_flip() + theme(legend.position = "top");
g <- g + labs(x = "Course Name")
g <- g + labs(y = "Number of Students")
g;

#示例数据
种子集（2017）；
为此：