geom_text标签在堆叠柱状图中重复显示问题求助

问题原因 #

你的数据中存在同一week_ending（周结束日期）和variant（毒株变体）对应多行记录的情况。未做聚合处理时，每一行记录都会在堆叠柱状图中生成一个细分段，且只要该行share（占比）大于0.1，就会添加一个标签——这直接导致同一变体在同一周内出现多个重复标签。

解决方案 #

绘图前先按周和变体分组，将同一变体在同一周内的占比求和，确保每个周-变体组合仅保留一行记录。这样每个变体在每周的堆叠段中只会生成一个标签。

调整后的代码 #

library(ggplot2)
library(dplyr)
library(magrittr)

variant_url <- "https://data.cdc.gov/api/views/jr58-6ysp/rows.csv"

variant_data <- read.csv("C:/<your download path here>/SARS-CoV-2_Variant_Proportions.csv", header = TRUE,
                         stringsAsFactors = FALSE)

variant_data$week_ending <- as.Date(variant_data$week_ending, format = "%m/%d/%Y")

# 新增分组聚合步骤，合并同一周同一变体的占比
USA_variant_data <- variant_data %>% 
  filter(usa_or_hhsregion == "USA", week_ending >= "2022-06-01") %>%
  group_by(week_ending, variant) %>%
  summarize(share = sum(share), .groups = "drop") %>%  # 求和并取消分组
  select(week_ending, variant, share)

USA_variant_bar <- USA_variant_data %>% ggplot(aes(fill=variant, y=share, x=week_ending)) +
  geom_bar(position="fill", stat="identity") +
  geom_text(aes(label=ifelse(share >0.1, variant,"")), position=position_fill(vjust=0.5), size = 2) +
  labs(x = "",
       y = "Percent of genomes sequenced") +
  theme(plot.title = element_text(size = rel(1), face = "bold"),
        plot.subtitle = element_text(size = rel(0.7)),
        plot.caption = element_text(size = rel(1)),
        axis.text.y = element_text(color='forestgreen'),
        axis.title.y = element_text(color="forestgreen"),
        axis.text.x = element_text(angle = 45,hjust = 1))

print(USA_variant_bar)

内容的提问来源于stack exchange，提问作者jerH