我有一个随时间推移的课程注册数据集，如start_date和end_date所示，约为50,000个ID。我有兴趣在特定时间范围内捕获该组的注册和未注册时段，特别是来自＆＃39; 2001-06-01＆＃39;到2015-01-01＆＃39;即使数据早些时候回来了。我有兴趣为每个id创建行，这些行捕获这些注册/未注册期间的日期间隔，并创建一个对这些期间进行分类的附加变量; ＆＃39;在注册之前，＃39;注册＆＃39;，＆＃39;之间注册＆＃39;，＆＃39;从未注册过＆＃39;。
澄清;
一些示例数据
id = c(1,3,3,3,5,5) entry_date = c(NA, '1996-05-09', '2005-12-12', '2013-12-19', '2011-11-05','2012-12-10') exit_date = c(NA, '2005-12-10', '2008-12-10', '2016-01-01', '2016-09-01', '2013-02-20') test
id entry_date exit_date 1 NA NA 3 1996-05-09 2005-12-10 3 2005-12-12 2008-12-10 3 2013-12-19 2016-01-01 5 2011-11-05 2012-09-01 5 2012-12-10 2013-02-20
我的预期输出是;
id entry_date exit_date category 1 2001-06-01 2016-01-01 Never enrolled 3 2001-06-01 2005-12-10 Enrolled 3 2005-12-10 2005-12-12 Between enrollment 3 2005-12-12 2008-12-10 Enrolled 3 2008-12-10 2013-12-19 Between enrollment 3 2013-12-19 2016-01-01 Enrolled 5 2001-06-01 2011-11-05 Prior to enrollment 5 2011-11-05 2012-09-01 Enrolled 5 2012-09-01 2012-12-10 Between enrollment 5 2012-12-10 2013-02-20 Enrolled 5 2013-02-20 2016-01-01 Between enrollment
任何有关如何实现此类目标的帮助都会非常感激！