R ggplot2使用jitter时如何将关联的收入支出数据点成对绑定？

你的需求核心是同ID对应的收入、支出点使用完全相同的抖动偏移量，避免二者错位，以下是两种可直接运行的实现方案：

方案1：内置position参数实现（代码最简） #

直接利用ggplot2的position_jitterdodge，将ID设为分组变量，设置躲避宽度为0，即可保证同组（同ID）的两点不会错开，仅整体做抖动偏移：

library(ggplot2)
ccode <- c(Gain="darkseagreen", Spend="darkblue")
ef<-data.frame(
  date=as.Date(c("2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-01","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-02","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03","2021-03-03")),
  site=c("Castle","Temple","Temple","Temple","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Castle","Castle","Temple","Temple","Palace","Castle","Temple","Temple","Temple","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Temple","Temple","Palace","Palace","Castle","Castle","Castle","Castle","Castle","Temple","Temple","Palace"),
  id=c("C123","T101","T93","T94","T95","T96","P102","P96","C126","C127","C128","T100","T98","P100","P98","C129","C130","C131","C132","C133","T104","T99","P99","C123","T101","T93","T94","T95","T96","P102","P96","C126","C127","C128","T100","T98","P100","P98","C129","C130","C131","C132","C133","T104","T99","P99"),
  gainspend=c("Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Gain","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend","Spend"),
  amount=c(6,14,34,31,3,10,6,14,2,16,16,14,1,1,15,11,8,7,2,10,15,4,3,NA,NA,4,5,NA,NA,NA,NA,NA,NA,2,NA,1,NA,3,NA,NA,2,NA,NA,2,NA,3))

ggplot(ef, aes(date, site, group = id)) + 
  geom_point(aes(size = amount, color = gainspend), alpha = 0.5,
             position = position_jitterdodge(jitter.width = 0,
                                             jitter.height = 0.2,
                                             dodge.width = 0)) +
  scale_color_manual(values = ccode) +
  scale_size_continuous(range = c(1,15), breaks = c(5,10,20))

方案2：手动生成固定偏移量（可控性最高） #

如果需要自定义偏移规则，可以提前给每个唯一ID分配固定的垂直偏移值，同ID的收入、支出点共用同一个偏移量，天然对齐：

library(ggplot2)
library(dplyr)
ccode <- c(Gain="darkseagreen", Spend="darkblue")

# 固定随机种子保证结果可复现
set.seed(123)
# 给每个ID生成唯一的垂直偏移量，范围和原jitter参数匹配
id_offset <- distinct(ef, id) %>% 
  mutate(y_offset = runif(n(), min = -0.2, max = 0.2))
# 合并偏移量到原数据集
ef <- left_join(ef, id_offset, by = "id")

ggplot(ef, aes(x = date, y = as.numeric(factor(site)) + y_offset)) + 
  geom_point(aes(size = amount, color = gainspend), alpha = 0.5) +
  # 还原y轴标签为站点名称
  scale_y_continuous(breaks = 1:nlevels(factor(ef$site)),
                     labels = levels(factor(ef$site)),
                     name = "site") +
  scale_color_manual(values = ccode) +
  scale_size_continuous(range = c(1,15), breaks = c(5,10,20))

两种方案均可以实现预期效果：同ID对应的绿色收入点和蓝色支出点完全中心对齐，同时整体添加抖动避免不同ID的点重叠。

内容的提问来源于stack exchange，提问作者schumacher