topic Re: Make a new variable from an existing variable in SAS Programming

Make a new variable from an existing variable

mariamon0 — Mon, 04 Mar 2019 21:22:25 GMT

I want to make a new variable from conditions of existing categorical variables in my dataset.

libname research "/home/mariamon0/";

data tobacco_;
set research.tobacco_;

these are the conditions:
if cigcur eq 1 or 2
if bidicur eq 1 or 2
if cigsmoker_new eq 0

and I want my new variable to be LCuser

how do I go about doing this?

Re: Make a new variable from an existing variable

PaigeMiller — Mon, 04 Mar 2019 21:29:41 GMT

these are the conditions:

if cigcur eq 1 or 2
if bidicur eq 1 or 2
if cigsmoker_new eq 0

Do you mean

if cigcur eq 1 or 2 AND
if bidicur eq 1 or 2 AND
if cigsmoker_new eq 0?

Or something else?

and I want my new variable to be LCuser

Do you want this to be YES or NO, or 0 or 1, or something else?

Can you give us the complete logic you want to follow?

Re: Make a new variable from an existing variable

mariamon0 — Mon, 04 Mar 2019 21:43:35 GMT

Yes all of those conditions must be there. I want the new variable LCuser to have all of these conditions

cigcur eq 1 or 2 AND
bidicur eq 1 or 2 AND
cigsmoker_new eq 0

Re: Make a new variable from an existing variable

Tom — Mon, 04 Mar 2019 21:54:55 GMT

What does

cigcur eq 1 or 2

mean?

SAS will interpret the OR as a binary boolean operator. No matter what value CIGUR has it will always be TRUE since the value to right of the OR is always true. (SAS considers and number that is not zero or missing as TRUE).

Did you mean:

cigcur in (1 2)

Re: Make a new variable from an existing variable

mariamon0 — Mon, 04 Mar 2019 21:57:05 GMT

Ok yes I wasn't aware of that. I want that variable to choose either the option 1 or the option 2. so yes I mean

cigcur in (1 2)

bidicur in (1 2)
cigsmoker_new eq 0

Re: Make a new variable from an existing variable

mariamon0 — Mon, 04 Mar 2019 22:02:58 GMT

cigcur eq 1 or 2 AND
bidicur eq 1 or 2 AND
cigsmoker_new eq 0

basically I want the new variable LCuser to have the following conditions

if the users cigcur said 1 or 2, if the bidicur users said 1 or 2 and if the cigsmokernew said 0.

Re: Make a new variable from an existing variable

mariamon0 — Mon, 04 Mar 2019 22:12:48 GMT

basically I want the new variable LCuser to have the following conditions

if the users cigcur said 1 or 2, if the bidicur users said 1 or 2 and if the cigsmokernew said 0.

Do I do if statements?

Lcusrer=if the users cigcur said 1 or 2, if the bidicur users said 1 or 2 and if the cigsmokernew said 0;

Re: Make a new variable from an existing variable

mariamon0 — Mon, 04 Mar 2019 22:55:29 GMT

yes I would have to use in.

not sure what the exact coding should be together

Re: Make a new variable from an existing variable

Tom — Tue, 05 Mar 2019 00:36:26 GMT

You have an IF but you don't say what you want to happen when the condition is true.

There are two types of IF statements in SAS.

There is the more traditional programming structure of the IF/THEN.

if condition then statement;

So when the condition after IF is true the statement after THEN executes. Typically this is an assignment statement. like:

if cigsmoker_new eq 0 then LCuser=1;

The other type of IF statement in SAS takes the form:

if condition ;

This is called a subsetting IF statement. If the condition is true then the data step iteration continues. If it is false then the data step iteration stops. None of the rest of the code in the data step executes, including any implicit OUTPUT at the end. So this is equivalent to this IF/THEN statement.

if not condition then delete;

So what you want is to make a dataset that had only observations that satisfy ALL of the conditions then you could use three subsetting if statements.

data want;
  set have;
  if cigcur in (1 2);
  if bidicur in (1 2);
  if cigsmoker_new eq 0;
run;

If you want to make a new variable named LCuser and set it to one if ANY of your three conditions is true then you could use:

data want;
  set have;
  LCuser=0;
  if cigcur in (1 2) then LCuser=1;
  if bidicur in (1 2) then LCuser=1;
  if cigsmoker_new eq 0 then LCuser=1;
run;

Or you could just make one IF statement and combine the conditions.

data want;
  set have;
  LCuser=0;
  if cigcur in (1 2) or  bidicur in (1 2) or cigsmoker_new eq 0 then LCuser=1;
run;

If you combine them with AND instead of OR then LCUser will be 1 only when ALL of the conditions are true instead of when ANY of them is true.