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rsubset

R subseting ID that have only one value in a column

I have a bird sighting dataset:

df
    # Bird.ID Location Date
    # 1 Plot1 22/02/2022
    # 2 Plot5 22/02/2022
    # 3 Plot1 22/02/2022
    # 1 Plot1 24/02/2022
    # 1 Plot1 26/02/2022
    # 1 Plot1 22/03/2022
    # 2 Plot5 22/03/2022
    # 2 Plot5 14/04/2022
    # 3 Plot2 14/04/2022
    # 3 Plot3 22/06/2022

I want to subset and keep only the individual that stayed in the same location through time. In this example I want to get rid of Individual "3" That was seen in 3 different location (plot1, 2 & 3) and keep only individual 1 (who stayed in plot1) & individual 2 (stayed in plot5)

The wanted output would be something like this:

output
    # Bird.ID Location Date
    # 1 Plot1 22/02/2022
    # 2 Plot5 22/02/2022
    # 1 Plot1 24/02/2022
    # 1 Plot1 26/02/2022
    # 1 Plot1 22/03/2022
    # 2 Plot5 22/03/2022
    # 2 Plot5 14/04/2022
Solution

  • A possible solution:

    library(dplyr)

df %>% 
  group_by(Bird.ID) %>% 
  filter(n_distinct(Location) == 1) %>% 
  ungroup

#> # A tibble: 7 × 3
#>   Bird.ID Location Date      
#>     <int> <chr>    <chr>     
#> 1       1 Plot1    22/02/2022
#> 2       2 Plot5    22/02/2022
#> 3       1 Plot1    24/02/2022
#> 4       1 Plot1    26/02/2022
#> 5       1 Plot1    22/03/2022
#> 6       2 Plot5    22/03/2022
#> 7       2 Plot5    14/04/2022