ggplot2分组柱状图顺序与数据框预设不一致问题求助

解决方案 #

你出现顺序错乱的核心原因有三点：

1. x轴映射的ValueEffects列为字符类型，ggplot默认按字母顺序排序，不会遵循你数据框的原有顺序
2. 你仅调整了分组列variable的因子水平，未同步处理x轴分类的顺序
3. y轴映射的value列为字符类型，无法正确映射柱状高度，也会干扰分组排序逻辑

按如下步骤调整即可：

第一步：预处理数据集，给分类变量设置指定顺序的因子水平，同时转换数值列 #

# 设置x轴分类顺序
GraphTableIndustry$ValueEffects <- factor(GraphTableIndustry$ValueEffects, 
                                          levels = c("MM Levered", "Leverage Effect", "MM Unlevered", "Multiple Effect", "Combination Effect", "Operating Improvements", "FCF Effect", "EBITDA Effect", "Revenue Effect", "Margin Effect", "Combination R/M Effect"))
# 设置fill分组（图例）顺序
GraphTableIndustry$variable <- factor(GraphTableIndustry$variable, 
                                      levels = c('Other', 'Medical & Health', 'IT', 'Industrial'))
# 将y轴值转为数值型
GraphTableIndustry$value <- as.numeric(GraphTableIndustry$value)

第二步：运行你原本的ggplot绘图代码即可得到符合预期顺序的图表 #

ggplot(GraphTableIndustry,
       aes(x = ValueEffects,
           y = value,
           fill = variable)) +
  geom_bar(stat = "identity",
           position = "dodge") +
  geom_text(aes(label = value),
            vjust = -0.5,
            color = "black",
            position = position_dodge(width = 0.9),
            size = 3.5) +
    theme(axis.line = element_blank(),
        axis.text.y = element_blank(),
        axis.text = element_text(
          size = 10,
          color = "black"),
        axis.ticks = element_blank(),
        axis.title.x = element_blank(),
        axis.title.y = element_blank(),
        panel.background = element_blank(),
        panel.border = element_blank(),
        panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        plot.background = element_blank(),
        legend.text = element_text(
          size = 10,
          color = "black"),
        legend.title = element_blank()
        ) +
  theme(legend.position = "bottom") +
  scale_fill_brewer(palette = "Blues", direction = -1)

内容的提问来源于stack exchange，提问作者bajk2019