r - 组内的 dplyr group_by() 和 slice()

Question

假设你有一个tibble:

library(tidyverse)

x <- tibble(
   name   = c("alice", "bob", "mary", "mary", "alice", "alice"),
   colour = c(NA, "green", "orange", "orange", NA, NA)
 ) %>% 
 group_by(name)



# A tibble: 6 x 2
# Groups:   name [3]
  name  colour
  <chr> <chr> 
1 alice NA    
2 bob   green 
3 mary  orange
4 mary  orange
5 alice NA    
6 alice NA  

如果一个组中的所有颜色都是 NA，您如何按名称分组并只返回 1 个名称？

预期输出:

# A tibble: 4 x 2
  name  colour
  <chr> <chr> 
1 alice NA    
2 bob   green 
3 mary  orange
4 mary  orange

Answer 1

您可以使用 all 内部过滤器来检查是否所有颜色都是 NA

x %>%
   filter(!(all(is.na(colour)) & 1:n() != 1))