点意味着通过箱线图组的中心垂直对齐，而不是在各自的箱线图上

Question

我正在使用截至 2024 年 3 月 17 日的最新版本的 R、R Studio、reshape2 和 ggplot2。

我有这个代码：

# Create long-form data
Apples.Long <- Apples[, 2:8]
Apples.Long <- melt(Apples.Long)
names(Apples.Long) <- c("Characteristic", "Score")

# Create boxplots
ggplot(data = Apples.Long, mapping = aes(x = Characteristic, y = Score, fill = Characteristic)) +
  geom_boxplot() +
  stat_boxplot(geom = "errorbar") +
  stat_summary(fun = "mean", shape = 20) +
  labs(x = NULL, caption = "Figure 1: Boxplots of characteristics") +
  theme_bw()

创建了这个数字：

我想创建另一个图形，但将数据分成两组。我有这段代码来尝试做到这一点：

# Create long-form data
Apples.Long <- Apples[, 2:9]
Apples.Long <- melt(Apples.Long)
names(Apples.Long) <- c("Quality", "Characteristic", "Score")

# Create boxplots
ggplot(data = Apples.Long, mapping = aes(x = Quality, y = Score, fill = Characteristic)) +
  geom_boxplot() +
  stat_boxplot(geom = "errorbar") +
  stat_summary(fun = "mean", shape = 20) +
  labs(x = NULL, caption = "Figure 4: Boxplots of characteristics by quality") +
  theme_bw()

创建了这个数字：

为什么均值的点沿着组的中心对齐？我该如何修复它？任何帮助表示赞赏。我在网上找不到任何相关信息，人工智能也没有多大帮助。

Answer 1

您需要在您的积分中添加

position_dodge2()

：

library(ggplot2)

ggplot(mpg, aes(x = factor(year), y = hwy, fill = class)) +
  geom_boxplot() +
  stat_boxplot(geom = "errorbar") +
  stat_summary(fun = "mean", shape = 20, position = position_dodge2(width = 0.75)) +
  theme_bw()