topic Re: Create variables in longitudinal data in SAS Programming

Create variables in longitudinal data

lalaktgrau — Mon, 15 Oct 2018 02:49:09 GMT

Hi all,

I have longitudinal data (1 obs per person per minute) with two time variables: date and time. I would like to create summary variables between 7pm on one day and 12 pm on the next day. How can I create this time interval using these two variables???

Thanks!

Re: Create variables in longitudinal data

Reeza — Mon, 15 Oct 2018 03:08:19 GMT

Show an example of your data please.
Instructions on how to do so are here. I would probably recommend a custom format.
https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-data-AKA-generate/tac-p/436960#M2686

Re: Create variables in longitudinal data

lalaktgrau — Mon, 15 Oct 2018 03:23:26 GMT

I combined date and time into one variable. I'd still only like to count people between certain time intervals.

data WORK.CLASS;
infile datalines truncover;
input Name:$8. sleep datetime;
informat datetime datetime20.;
format datetime datetime20.;
datalines;
Alfred 0 04MAR14:23:55:00
Alfred 0 04MAR14:23:56:00
Alfred 1 04MAR14:23:57:00
Alfred 1 04MAR14:23:58:00
Alfred 1 04MAR14:23:59:00
Alfred 1 04MAR14:00:00:00
Alfred 1 04MAR14:01:01:00
Alfred 1 04MAR14:01:02:00
Alfred 1 04MAR14:01:03:00
Alfred 1 04MAR14:01:04:00

mary 0 04MAR14:23:55:00
mary 0 04MAR14:23:56:00
mary 1 04MAR14:23:57:00
mary 1 04MAR14:23:58:00
mary 1 04MAR14:23:59:00
mary 1 04MAR14:00:00:00
mary 1 04MAR14:01:01:00
mary 1 04MAR14:01:02:00
mary 1 04MAR14:01:03:00
mary 1 04MAR14:01:04:00
;

Re: Create variables in longitudinal data

Reeza — Mon, 15 Oct 2018 03:27:47 GMT

Are your date intervals all over the place or do they have an upper and lower limit?

Re: Create variables in longitudinal data

lalaktgrau — Mon, 15 Oct 2018 03:28:53 GMT

I have one week per person, every single minute!

Re: Create variables in longitudinal data

Reeza — Mon, 15 Oct 2018 03:34:55 GMT

I understand that, but is there a starting date and end date that you know, ie the data is all between 2014 and 2018?

@lalaktgrau wrote:

I have one week per person, every single minute!

Re: Create variables in longitudinal data

lalaktgrau — Mon, 15 Oct 2018 03:37:12 GMT

No! It's all over the place. Different people had different starts and ends. I just want to pull all the nighttime data, so I think we can disregard the dates (except to know start of night one day, morning the next day 7pm-12pm).

Re: Create variables in longitudinal data

Reeza — Mon, 15 Oct 2018 03:47:49 GMT

You can't disregard the dates, since you need to account for the time, unless you're absolutely positive you have a record for every single minute. In that case you could just do a simple IF/THEN comparison. But from the first to last date you would have no breaks.

Re: Create variables in longitudinal data

Reeza — Mon, 15 Oct 2018 03:54:26 GMT

I can't test with your sample data because there's no day, it's all night.

Re: Create variables in longitudinal data

shahparth260 — Mon, 15 Oct 2018 03:58:01 GMT

Hello, can you explicitly specify your output ? if possible.

what is meaning for 0 and 1 ?
is it yes or no ?

Re: Create variables in longitudinal data

Reeza — Mon, 15 Oct 2018 03:59:34 GMT

On second thought, not sure it matters either. Try this:

data want;
set have;

if hour(timepart(datetime)) >= 19 or hour(timepart(datetime)) <= 12 then interval='Night';
else interval = 'Day';

run;