Create New Variable Based on Certain Conditions

[chester2018]

Hi everyone!

I'm creating a new variable, and I'm having issues with the IF-THEN-ELSE statements. For my variable, I would like to calculate the weekly minutes only if that participant has a MET value (either Moderate or Vigorous). Therefore, people without a MET value won't get the calculation.

So, participants may or may not have a MET value (indicated by Vigorous or Moderate). If they do have a MET value, I would like to calculate their average weekly activity (min_week = ((a*b*7)/30)). So, if someone with a MET value =., I don't want to give them an average weekly activity.

Hope I made some sense

data exercise.writeinsMETS;
	set exercise.writeinsMETS;
	if METS="Vigorous" or METS = "Moderate";
	else if writein38_min_week=((v5qa38a*v5qa38b*7)/30);
	else if writein39_min_week=((v5qa39a*v5qa39b*7)/30);
	else if writein40_min_week=((v5qa40a*v5qa40b*7)/30);
	else max(writein38_min_week, writein39_min_week,writein40_min_week) = .;
run;

The attached data portion is something I don't want. The highlighted values in the min_week columb need to be missing

[andreas_lds]

data exercise.writeinsMETS;
	set exercise.writeinsMETS;

 You should not overwrite the source dataset during development, an i would not do this even after the code has been tested.

if METS="Vigorous" or METS = "Moderate";
else if writein38_min_week=((v5qa38a*v5qa38b*7)/30);

A subsetting-if has no else part, so this will give you a syntax error.

To make it easier to understand the task, please post data in usable form an show the expected result.

I don't see the need for that many if-statements, but maybe i don't understand what you are trying to do.

[fja]

Hello!

If you do not write anything in case of MET value = .  to the output dataset, then you could use:

if <condition> then delete;

to continue with the next line. Hope I understood you correctly.

--FJa

[ChrisHemedinger]

For anyone getting started with the nuances of the IF-THEN-ELSE statements in the SAS DATA step, I recommend this short tutorial by @brzcol: