I just realize there is an underlining problem in my code. Sorry. data data1 ; input subject        visit                 days           inr ; cards;       1                1                  0               1.4       1                2                  3               1.5       1                3                  6               1.6       1                4                 11              1.4      1                5                 13              1.7    1                6                 28              1.8       2                1                  2               1.5       2                2                  5               1.7 ; run; %let weeks=3; data week; do i=0 to &weeks;   days=7*i;output; end; drop i; run; proc sql; create table key as   select * from (select distinct subject from data1),week    order by subject,days; quit; data want; set data1 key(in=inb); by subject days; v=lag(visit);d=lag(days);i=lag(inr); if inb and not lag(inb) and subject=lag(subject) then do;time=days;output;end; drop visit days inr; run; Xia Keshan ... View more

Dear Sir, Good Morning from Chennai City, India as it is 2:13AM here. Thank you so much for noticing my mention and for the humble courtesy in replying to my post. I have followed many of your posts thoroughly since 2011 and that's the time I started my career in SAS programming/Analysis. I am fully aware and in awe of your accomplishments all the way through(1970's-till present) in your SAS endeavors and trust me, I am amazed to hear of your popularity across the globe wherever I have travelled, be it Europe, America’s, Singapore and beyond. I have read your interviews online and many more SAS activities of yours. To use a metaphor for comparison, they call you “Roger federer of SAS”, as he is for Tennis sport. For whatever reason, my interest in SAS programming spurred only in Feb 2014 of this year, perhaps as I turned 31 years of age feeling old (smiles) and regretting to have not accomplished anything in the last 3 years has led my eyes wide open every time to have noticed you et al like PG/Xia Keshan post an amazing immaculate code. Of course, with daily hard work and perseverance this year, I certainly am better than previous day, however I believe it would be unparalleled to gain superior speed and knack in applying the efficient technique as Xia Keshan did in this thread if you (super experts) were to train folks like me. Anyways, I can’t thank you enough as I confess to have shamelessly used your code as a verbatim for my work in my past and I bet several others are doing it too. I guess that is really I can think of to write. Thanks for reading and Merry Christmas!!!!. Cheers, Naveen ... View more