topic Re: Creating a new variable calculated from values of different lines in Mathematical Optimization, Discrete-Event Simulation, and OR

Creating a new variable calculated from values of different lines

Engel — Tue, 27 Nov 2012 19:12:39 GMT

Dear SAS experts, In my data set (animal behavior) I would like to create a new variable: the time interval between two events. There exists the variables 'first (starting time of behavior)’ and 'Last (ending time of behavior)' per line (see attached table). I am interested in the time interval between 'last' in line n and 'first' in line n + 1. I really appreciate your help 🙂

Re: Creating a new variable calculated from values of different lines

art297 — Tue, 27 Nov 2012 19:22:28 GMT

Can't you just use the lag function? e.g.:

libname art "c:\art";

data want;

format difference time8.;

set art.inter;

by datum name;

last_last=lag(last);

if first.name then call missing(last_last);

difference=first-last_last;

run;

Re: Creating a new variable calculated from values of different lines

Engel — Tue, 27 Nov 2012 19:34:00 GMT

Dear Arthur, thank you very much! It is exactly what I wanted. Best regards from Germany Engel

Re: Creating a new variable calculated from values of different lines

Haikuo — Tue, 27 Nov 2012 19:35:38 GMT

Echo with Art, you can also use dif(); sorry, Art, for stealing your code:

data want;

format difference time8.;

set art.inter;

by datum name;

/* last_last=lag(last);

if first.name then call missing(last_last);*/

difference=ifn(first.name,.,dif(last));

run;

Haikuo

Re: Creating a new variable calculated from values of different lines

art297 — Tue, 27 Nov 2012 20:11:34 GMT

: I don't mind your "stealing" the code, but your solution doesn't meet the OP's requirements. You are taking the difference between last and the previous last. The OP wanted the difference between the current first and the previous last.

Re: Creating a new variable calculated from values of different lines

Haikuo — Tue, 27 Nov 2012 21:20:51 GMT

Oops, my bad. Now I know why you choose to use lag(). Haikuo