SAS assign group and accumulate

[MM88]

Hi experts,

I have a dataset which have columns Event and Time. I need to create columns Group and Cumulative. What I need to measure is the duration of the Event 'Event1_Stop' until an 'Event1_Start' appears. Last group should sum the time meaning that the stop is ongoing and no start for the event has entered.
My data sample is:

data have;
length Event $15;
input Event $ Time;
datalines;
Event3_Start 0.2
Event2_Start 0.4
Event2_End 0.2
Event1_Stop 0.2
Event3_Start 0
Event4_Start 0.5
Event3_Stop 0.2
Event1_Start 0
Event4_Stop 0
Event4_Stop 0
Event1_Stop 0.3
Event3_Start 0.3
Event1_Start 0
Event3_Start 0.4
Event3_Stop 0
Event1_Stop 0.2
Event3_Start 0.2
Event2_Start 0.4
run;

The result dataset that I need to obtain is:

data have;
length Event $15;
input Event $ Time Group Cumulative;
datalines;
Event3_Start 0.2 0 0
Event2_Start 0.4 0 0
Event2_End 0.2 0 0
Event1_Stop 0.2 1 0.9
Event3_Start 0 1 0
Event4_Start 0.5 1 0
Event3_Stop 0.2 1 0
Event1_Start 0 0 0
Event4_Stop 0 0 0
Event4_Stop 0 0 0
Event1_Stop 0.3 2 0.6
Event3_Start 0.3 2 0
Event1_Start 0 0 0
Event3_Start 0.4 0 0
Event3_Stop 0 0 0
Event1_Stop 0.2 3 0.8
Event3_Start 0.2 3 0
Event2_Start 0.4 3 0
run;

Thanks for your suggestions.
Regards.

[mkeintz · Accepted solution]

First, thank you for posting the sample starting data and expected results in working data steps.  This made it possible for me to understand the objective, and to test my suggestion, which follows:
 
data have;
length Event $15;
input Event $ Time;
datalines;
Event3_Start 0.2
Event2_Start 0.4
Event2_End 0.2
Event1_Stop 0.2
Event3_Start 0
Event4_Start 0.5
Event3_Stop 0.2
Event1_Start 0
Event4_Stop 0
Event4_Stop 0
Event1_Stop 0.3
Event3_Start 0.3
Event1_Start 0
Event3_Start 0.4
Event3_Stop 0
Event1_Stop 0.2
Event3_Start 0.2
Event2_Start 0.4
run;
data stop_to_start (keep=group cumulative);
set have end=end_of_have;
group+(event='Event1_Stop');
if event='Event1_Stop' then cumulative=0;
cumulative+time;
if end_of_have or event='Event1_Start' ;
run;

data want;
set have;
if _n_=1 or event='Event1_Start' then group=0;
cumulative=0;
if event='Event1_Stop' then set stop_to_start;
run;
The strategy here is to make an intermediate dataset, stop_to_start with one observation per time span , containing two variables: cumulative and group.
 
Then just read HAVE, set cumulative to 0, and read a stop_to_start observation only when you encounter an Event1_Stop record from have.  This updates cumulative and group.
 
Because the group variable is read by a SET stop_to_start statement, it is automatically retained  So resetting it to zero when you encounter an Event1_Start observation, it will be propagated as zero until the next Event1_Stop.
 

[MM88]

Thanks @mkeintz, your answer was very helpful. Sorry for the late reply, I was modifying your code to fullfill other restrictions on my data.