r - 当有多个数据点时复制信息

Question

我有一个数据清理问题。数据收集发生了三次，有时数据输入不正确。因此，如果学生多次收集数据，则需要复制第二个数据点。

这是我的数据集:

df <- data.frame(id = c(1,1,1, 2,2,2, 3,3,  4,4, 5),
                 text = c("female","male","male", "female","female","female", "male","female","male", "female", "female"),
                 time = c("first","second","third", "first","second","third", "first","second","second", "third", "first"))
            
> df
   id   text   time
1   1 female  first
2   1   male second
3   1   male  third
4   2 female  first
5   2 female second
6   2 female  third
7   3   male  first
8   3 female second
9   4   male second
10  4 female  third
11  5 female  first

因此 id 1,3, 4 的性别信息不正确。当有关于 gender 变量的多个/不同输入时，我需要复制 second 数据点。如果只有一个数据点，那应该保留在数据集中。

期望的输出是

> df1
   id   text   time
1   1   male  first
2   1   male second
3   1   male  third
4   2 female  first
5   2 female second
6   2 female  third
7   3 female  first
8   3 female second
9   4   male second
10  4   male  third
11  5 female  first

有什么想法吗？谢谢!

Answer 1

只是另一种有趣的方法；

library(dplyr)

df %>% 
  filter(time =="second") %>% 
  select(-time) %>% 
  full_join(df, ., by ="id", suffix = c("_old", "")) %>% 
  mutate(text = coalesce(text, text_old)) %>% 
  select(names(df))

#>       id text   time  
#>  1     1 male   first 
#>  2     1 male   second
#>  3     1 male   third 
#>  4     2 female first 
#>  5     2 female second
#>  6     2 female third 
#>  7     3 female first 
#>  8     3 female second
#>  9     4 male   second
#> 10     4 male   third 
#> 11     5 female first