Trim grouping structure

Drop unused levels of all factors that are used as grouping variables, then recalculates the grouping structure.

group_trim() is particularly useful after a filter() that is intended to select a subset of groups.

group_trim(.tbl, .drop = group_by_drop_default(.tbl))

Arguments

.tbl	A grouped data frame
.drop	See group_by()

Value

A grouped data frame

See also

Other grouping functions: group_by(), group_map(), group_nest(), group_split()

Examples

iris %>%
  group_by(Species) %>%
  filter(Species == "setosa", .preserve = TRUE) %>%
  group_trim()
#> # A tibble: 50 x 5
#> # Groups:   Species [1]
#>    Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#>           <dbl>       <dbl>        <dbl>       <dbl> <fct>  
#>  1          5.1         3.5          1.4         0.2 setosa 
#>  2          4.9         3            1.4         0.2 setosa 
#>  3          4.7         3.2          1.3         0.2 setosa 
#>  4          4.6         3.1          1.5         0.2 setosa 
#>  5          5           3.6          1.4         0.2 setosa 
#>  6          5.4         3.9          1.7         0.4 setosa 
#>  7          4.6         3.4          1.4         0.3 setosa 
#>  8          5           3.4          1.5         0.2 setosa 
#>  9          4.4         2.9          1.4         0.2 setosa 
#> 10          4.9         3.1          1.5         0.1 setosa 
#> # … with 40 more rows