My ggplot bar chart reorder（）函数的值为'；行不通

我试图将条形图按降序排列（接触率最高的道路组位于顶部）。但是，reorder（）函数似乎不起作用

    for (i in uniq_wards) 
  { print(ggplot(data = subset(roads, Ward == i),
               aes(x = reorder(Roadgroup, Contact.rate),
                   y = Contact.rate,
                   fill = undecided_rate)) +
          geom_col() +
          coord_flip() +
          labs(fill = "Undecided rate", y = "Contact Rate", x = "Road Group") +
          theme(axis.text.x = element_text(angle = 90),
                text = element_text(size = 8)) +
          scale_fill_gradient(low = "gray", high = "blue", limits=c(0.0, 0.35)) +
          ggtitle(i, subtitle = "Contact Rate and Undecided Density")) 
  }

第二幅图是降序的一个示例，我希望第一个图是这样的，它使用相同的变量axis reorder（）代码：

---

没有数据很难提供帮助。你可以试试下面的方法。我只在您的原始代码中添加了

FUN=sum

。如果不起作用，请提供一些示例数据

library(tidyverse) 
    for (i in uniq_wards) 
  { print(ggplot(data = subset(roads, Ward == i),
               aes(x = reorder(Roadgroup, Contact.rate, FUN = sum),
                   y = Contact.rate,
                   fill = undecided_rate)) +
          geom_col() +
          coord_flip() +
          labs(fill = "Undecided rate", y = "Contact Rate", x = "Road Group") +
          theme(axis.text.x = element_text(angle = 90),
                text = element_text(size = 8)) +
          scale_fill_gradient(low = "gray", high = "blue", limits=c(0.0, 0.35)) +
          ggtitle(i, subtitle = "Contact Rate and Undecided Density")) 
  }

---

欢迎来到SO。请看一看。你更有可能得到答案

library(tidyverse) 
    for (i in uniq_wards) 
  { print(ggplot(data = subset(roads, Ward == i),
               aes(x = reorder(Roadgroup, Contact.rate, FUN = sum),
                   y = Contact.rate,
                   fill = undecided_rate)) +
          geom_col() +
          coord_flip() +
          labs(fill = "Undecided rate", y = "Contact Rate", x = "Road Group") +
          theme(axis.text.x = element_text(angle = 90),
                text = element_text(size = 8)) +
          scale_fill_gradient(low = "gray", high = "blue", limits=c(0.0, 0.35)) +
          ggtitle(i, subtitle = "Contact Rate and Undecided Density")) 
  }