如何在ggplot数值轴点图添加回归线或横向堆叠重叠点

方案一：数值型X轴实现无重叠点图+回归线 #

不用转因子，换用以下方法解决点重叠问题，同时保留数值X轴以正常添加回归线：

方法1：用geom_jitter添加可控偏移 #

给点添加随机水平偏移，避免重叠，偏移范围可通过width参数调整：

ggplot(data = plotting, aes(x = x, y = y, color = separator)) +
  geom_jitter(width = 0.2, height = 0, size = 2, alpha = 0.8) +
  scale_color_manual(values=c("palevioletred3", "deepskyblue3")) +
  geom_smooth(data = subset(plotting, separator == 0), method = "lm", se = FALSE, color = "violetred3") +
  geom_smooth(data = subset(plotting, separator == 1), method = "lm", se = FALSE, color = "dodgerblue3") +
  labs(title = "Learning and Learner Enjoyment",
       x = "Learner Enjoyment",
       y = "Learning")

方法2：用geom_beeswarm实现规整分布（需ggbeeswarm包） #

点会沿X轴均匀分散，比jitter的随机偏移更规整：

# 先安装依赖包：install.packages("ggbeeswarm")
library(ggbeeswarm)

ggplot(data = plotting, aes(x = x, y = y, color = separator)) +
  geom_beeswarm(size = 2, alpha = 0.8) +
  scale_color_manual(values=c("palevioletred3", "deepskyblue3")) +
  geom_smooth(data = subset(plotting, separator == 0), method = "lm", se = FALSE, color = "violetred3") +
  geom_smooth(data = subset(plotting, separator == 1), method = "lm", se = FALSE, color = "dodgerblue3") +
  labs(title = "Learning and Learner Enjoyment",
       x = "Learner Enjoyment",
       y = "Learning")

方法3：用geom_count展示重叠密度 #

用点的大小表示该位置的重叠点数，直观展示数据分布密度：

ggplot(data = plotting, aes(x = x, y = y, color = separator)) +
  geom_count(alpha = 0.8) +
  scale_color_manual(values=c("palevioletred3", "deepskyblue3")) +
  geom_smooth(data = subset(plotting, separator == 0), method = "lm", se = FALSE, color = "violetred3") +
  geom_smooth(data = subset(plotting, separator == 1), method = "lm", se = FALSE, color = "dodgerblue3") +
  labs(title = "Learning and Learner Enjoyment",
       x = "Learner Enjoyment",
       y = "Learning")

方案二：因子型X轴添加回归线并保留原数值标签 #

如果偏好geom_dotplot的展示效果，可通过以下步骤实现：

1. 构建因子时绑定原X值的标签
2. 在geom_smooth中明确使用原数值型X变量（线性回归需要数值输入）

示例代码：

# 构建带原数值标签的因子列（假设原X值范围是5-10）
plotting$factor_x <- factor(plotting$x, levels = 5:10)

ggplot(data = plotting, aes(x = factor_x, y = y, color = separator, fill = separator)) +
  geom_dotplot(binaxis = "y", dotsize = 0.5, stackgroups = TRUE, stackdir = "center", binpositions = "all") +
  scale_color_manual(values=c("palevioletred3", "deepskyblue3")) +
  # 手动指定geom_smooth的x为原数值型变量
  geom_smooth(data = subset(plotting, separator == 0), aes(x = x), method = "lm", se = FALSE, color = "violetred3") +
  geom_smooth(data = subset(plotting, separator == 1), aes(x = x), method = "lm", se = FALSE, color = "dodgerblue3") +
  labs(title = "Sample",
       x = "Learner Enjoyment",
       y = "Learning") +
  # 确保X轴显示原5-10的数值标签
  scale_x_discrete(labels = 5:10)

内容的提问来源于stack exchange，提问作者quinfog