Calculate interval values

[ursula]

HI there;

I would like to calculate the interval between values by ID,  as following:

ID	value	wants
A	39	39
A	45	6	= 45-39
B	38	38
B	40	2	= 40-38
B	45	5	= 45-40
C	37	37
C	40	3	= 40-37
C	42	2	= 42-40
D	40	40

the column 'wants' is what I want to get.

Hope it's not confused you.

Thanks in advace.

[Astounding · Accepted solution]

SAS knows how to do this, as long as your data set is sorted by ID:

data want;

set have;

by ID;

wants = dif(value);

if first.id then wants = value;

run;

[ursula]

Thank you very much, Astounding.

I appreciate your prompt response!