applying a function to combinations of groups, holding 1 group fixed
问题 I have some data which looks like: grp date id Y <chr> <dttm> <chr> <dbl> 1 group1 2020-09-01 00:00:00 04003 17039. 2 group1 2020-09-01 00:00:00 04006 13233. 3 group1 2020-09-01 00:00:00 04011_AM 7918. 4 group1 2020-09-01 00:00:00 0401301_AD 22586. 5 group1 2020-09-01 00:00:00 0401303 20527. 6 group1 2020-09-01 00:00:00 0401305 29422. 7 group2 2020-09-01 00:00:00 22017_AM 7088. 8 group2 2020-09-01 00:00:00 22021_AM 8134. 9 group2 2020-09-01 00:00:00 22039_AM 15842. 10 group2 2020-09-01 00:00