使用GGPLOT对比两组内多变量均值并绘制分组柱状图

我们可以用dplyr处理数据计算均值，ggplot2绘制柱状图，再用patchwork（或gridExtra）将两个图横向拼接，实现需求效果。

步骤1：加载所需包 #

library(dplyr)
library(ggplot2)
library(patchwork) # 用于拼接图形

步骤2：计算各组各Score变量的均值 #

先对数据分组，计算每个Score变量的均值，并将宽格式数据转为长格式，方便绘图：

mean_scores <- DB %>%
  group_by(Group) %>%
  summarise(across(starts_with("Score"), mean)) %>%
  pivot_longer(cols = starts_with("Score"), names_to = "Score", values_to = "Mean")

步骤3：绘制两个柱状图并拼接 #

分别绘制两组的均值柱状图，再横向排列：

# Group 2的均值柱状图
p_group2 <- ggplot(filter(mean_scores, Group == "2"), aes(x = Score, y = Mean)) +
  geom_col(fill = "#3498db") +
  labs(title = "Group 2 mean scores", x = "Score变量", y = "均值") +
  theme_minimal()

# Group 1的均值柱状图
p_group1 <- ggplot(filter(mean_scores, Group == "1"), aes(x = Score, y = Mean)) +
  geom_col(fill = "#2ecc71") +
  labs(title = "Group 1 mean scores", x = "Score变量", y = "均值") +
  theme_minimal()

# 横向拼接两个图
p_group2 + p_group1

替代方案（无patchwork时） #

如果未安装patchwork，可以用gridExtra包的grid.arrange实现拼接：

library(gridExtra)
grid.arrange(p_group2, p_group1, ncol = 2)

内容的提问来源于stack exchange，提问作者Sari Katish