在R中基于数据框多列多行生成样本最终结果列的问题

方法一：Base R 实现 #

利用ave()函数按sample_ID分组判断，快速生成目标列：

# 先构造示例数据框（可替换为你的实际数据）
df <- data.frame(
  sample_ID = c("sample1", "sample1", "sample1", "sample2", "sample2", 
                "sample3", "sample3", "sample4", "sample4", "sample4"),
  date = c("1/1/2022", "1/1/2022", "1/1/2022", "2/1/2022", "3/1/2022", 
           "4/1/2022", "5/1/2022", "5/1/2022", "6/1/2022", "7/1/2022"),
  test_result = c("positive", "negative", "negative", "positive", "negative",
                  "negative", "positive", "negative", "negative", "negative")
)

# 添加final_result列
df$final_result <- ave(df$test_result, df$sample_ID, 
                       FUN = function(x) ifelse(any(x == "positive"), "positive", "negative"))

方法二：tidyverse（dplyr）实现 #

如果习惯管道式语法，用分组+突变的方式更直观：

library(dplyr)

df <- df %>%
  group_by(sample_ID) %>%
  mutate(final_result = ifelse(any(test_result == "positive"), "positive", "negative")) %>%
  ungroup()

两种方法都能达成需求：只要某样本存在任意一条positive结果，该样本所有行的final_result都为positive；全为negative则结果为negative。

内容的提问来源于stack exchange，提问作者Trang Nguyen