chickadee » dataframe » *filter-strategy-threshold*

A parameter (default 10000): df-filter-rows uses the bitmap strategy at or above this many rows, and the simpler row-rebuilding strategy below it.

If df is grouped (see Grouping and summarizing below), the result stays grouped by the same columns. A group left with no rows after filtering simply doesn't appear, the same way dplyr's filter() treats a grouped tibble.