Removing observations before 'beginning' and after 'ending' - SAS code - sas

Question

My table has some leading and trailing observations that I am trying to remove. I want to remove the rows that come before every 'begin' event and after every 'end' event for every single group. The table resembles the below:
| Time | Group | Event | Value |
| 1 | 1 | NA | 0 |
| 2 | 1 | NA | 0 |
| 3 | 1 | Begin | 1.1 |
| 4 | 1 | NA | 1.2 |
| 5 | 1 | NA | 1.3 |
| 6 | 1 | End | 1.4 |
| 7 | 1 | NA | 0 |
| 1 | 2 | NA | 0 |
| 2 | 2 | Begin | 1.1 |
| 3 | 2 | NA | 1.2 |
| 4 | 2 | End | 1.3 |
| 5 | 2 | NA | 1.4 |

Answer 1

On the presumption that the incoming data is already sorted and that there are zero or more serially bounded ranges of Begin to End within each group:
data want;
do until (last.group);
set have;
by group time;
if event = 'Begin' then _keeprow = 1;
if _keeprow then output;
if event = 'End' then _keeprow = 0;
end;
drop _keeprow;
end;

Answer 2

I have came out an easy way but will be limited by the actual data size.
data have;
input Time Group Event $ Value ;
datalines;
1 1 NA 0
2 1 NA 0
3 1 Begin 1.1
4 1 NA 1.2
5 1 NA 1.3
6 1 End 1.4
7 1 NA 0
1 2 NA 0
2 2 Begin 1.1
3 2 NA 1.2
4 2 End 1.3
5 2 NA 1.4
;
run;
proc sort data = have;
by group time;
run;
data have1;
set have;
count + 1;
by group;
if first.group then count = -100;
if event = 'Begin' then count = 0;
if event = 'End' then count = 100;
if count < 0 or count >100 then delete;
run;
The current code could be applied to the small size data if you have less than 100 observations between 'Begin' and 'End' and less than 100 observations before 'Begin'. You can adjust the initial count value according to the true data size.

Answer 3

one way to do is
data have;
input Time Group Event $ Value ;
datalines;
1 1 NA 0
2 1 NA 0
3 1 Begin 1.1
4 1 NA 1.2
5 1 NA 1.3
6 1 End 1.4
7 1 NA 0
1 2 NA 0
2 2 Begin 1.1
3 2 NA 1.2
4 2 End 1.3
5 2 NA 1.4
;
data have2(keep= Group min_var max_var);
set have;
by group;
retain min_var max_var;
if trim(Event)= "Begin" then min_var =_n_ ;
if trim(Event)= "End" then max_var =_n_;
if last.group;
run;
data want;
merge have have2;
by group;
if _n_ ge min_var and _n_ le max_var ;
drop min_var max_var;
run;