Creating new data periods from yearly snapshot

[Jane7476]

Hi All,

I am struggling to create new FROM and VALID to dates from yearly snapshots. I need to create the dates based on change in HEIGHT. I have posted a IN and OUT data. Please see if you could help. Need to create the out data.

data in;

informat id 1. valid_from MMDDYY10. valid_to MMDDYY10. height 8.;

input id valid_from valid_to height;

format valid_from date9. valid_to date9.;

cards;

1 01/01/2010 01/01/2011 3

1 01/01/2011 01/01/2012 4

1 01/01/2012 01/01/2013 4

1 01/01/2013 01/01/2014 4

1 01/01/2014 01/01/2015 13

1 01/01/2015 01/01/2016 3

2 01/01/2011 01/01/2012 20

2 01/01/2012 01/01/2013 20

2 01/01/2013 01/01/2014 21

;

run;

data out;

informat id 1. valid_from MMDDYY10. valid_to MMDDYY10. height 8.;

input id valid_from valid_to height;

format valid_from date9. valid_to date9.;

cards;

1 01/01/2010 01/01/2011 3

1 01/01/2011 01/01/2014 4

1 01/01/2014 01/01/2015 13

1 01/01/2015 01/01/2016 3

2 01/01/2011 01/01/2013 20

2 01/01/2013 01/01/2014 21

;

run;

[novinosrin]

proc sort data=in;

by id ;

run;

data out;

set in;

by id height notsorted;

if last.height;

run;

Regards,

Naveen Srinivasan

 Edited: I missed to read your question properly. Well, in any case when Xia keshan answers, one can blindly copy the genius. My apologies!

[Jane7476]

Thanks for replying. Yes it didn't take into account changing the from data in row 2 to 2011 - except that it works fine.

I had totally forgotton about the notsorted option...that was the missing like for me. Thanks

[Ksharp · Accepted solution]

data in;
informat id 1. valid_from MMDDYY10. valid_to MMDDYY10. height 8.;
input id valid_from valid_to height;
format valid_from date9. valid_to date9.;
cards;
1 01/01/2010 01/01/2011 3
1 01/01/2011 01/01/2012 4
1 01/01/2012 01/01/2013 4
1 01/01/2013 01/01/2014 4
1 01/01/2014 01/01/2015 13
1 01/01/2015 01/01/2016 3
2 01/01/2011 01/01/2012 20
2 01/01/2012 01/01/2013 20
2 01/01/2013 01/01/2014 21
;
run;
 
data want;
 set in;
 by id height notsorted;
 retain temp;
 if first.height then temp=valid_from;
 if last.height then do;valid_from=temp;output;end;
 drop temp;
run;