从r中的列中删除重复元素

Question

考虑到下面的示例向量(类是数字的)：

dates <- data.frame(A = c(2021, 2022, 2022, 2022, 2022, 2022, 2022, 2022, 2022, 2023, 
2023, 2023, 2023, 2024, 2025, 2025, 2025, 2025), B = "something")

我想删除重复的任何一个守护进程：

dates <- data.frame(A = c(2021, 2022, NA, NA, NA, NA, NA, NA, NA, 2023, 
NA, NA, NA, 2024, 2025, NA, NA, NA), B = "something")

Answer 1

下面是如何使用mutate实现akrun的解决方案

library(dplyr)
dates %>% 
  mutate(A = replace(A, duplicated(A), NA))

  A         B
1  2021 something
2  2022 something
3    NA something
4    NA something
5    NA something
6    NA something
7    NA something
8    NA something
9    NA something
10 2023 something
11   NA something
12   NA something
13   NA something
14 2024 something
15 2025 something
16   NA something
17   NA something
18   NA something

Answer 2

使用duplicated

dates$A <- replace(dates$A, duplicated(dates$A), NA)

或更新原始对象。

dates$A[duplicated(dates$A)] <- NA

如果这些是基于相邻的值，请使用rle

dates$A <- replace(dates$A, duplicated(with(rle(dates$A), 
     rep(seq_along(values), lengths))), NA)

如果我们想要删除行

subset(dates, !duplicated(A))