topic Re: Recoding multiple variables at once in SAS Programming

Recoding multiple variables at once

knargis160 — Fri, 13 Mar 2020 14:04:05 GMT

I want to code for multiple variables from level 0 to 2 at once. what is the best wat to do in SAS rather than using if-else statements?

Re: Recoding multiple variables at once

PaigeMiller — Fri, 13 Mar 2020 14:07:04 GMT

You could use ARRAYs. Then you need only one if-then statement. But since you give us no information about your data set variable names, we can't provide any more details.

Re: Recoding multiple variables at once

PeterClemmensen — Fri, 13 Mar 2020 14:06:49 GMT

Depends.. Can you be a bit more precise about the nature of your problem?

Re: Recoding multiple variables at once

ed_sas_member — Fri, 13 Mar 2020 14:08:24 GMT

Hi @knargis160
You can use an array to perform the same operation on multiple variables:

Data want;
Set have;
Array _arr(*) var1 var2 var3 ;
Do i=1 to dim(_arr);
If _arr(i)=0 then _arr(i)=2;
End;
Drop i;
Run;

Re: Recoding multiple variables at once

ballardw — Fri, 13 Mar 2020 16:28:12 GMT

@knargis160 wrote:

I want to code for multiple variables from level 0 to 2 at once. what is the best wat to do in SAS rather than using if-else statements?

Another approach can be when you read the data from an external source. (informat and example data changed from first response)

proc format library=work;
invalue changetwo
'0'=2
other=_same_
;
run;

data example;
   informat x y z changetwo.;
   input x y z;
datalines;
1 0 2
0 0 0
1 1 0;

A question though. Are you changing 0 to 2 because you have a dichotomous variable that has 1 for 'Yes' 'True' 'Present' and 0 for 'No' 'False' 'Absent' or similar? You may want to strongly consider not doing so. It can require more code to get somethings done with 1/2 coding than with 1/0 coding.

Consider: if you SUM a 1/0 coded variable then the total is the number of observations or variables that were coded 1.

The MEAN is the percentage of 1 values in decimal form.

Re: Recoding multiple variables at once

Reeza — Fri, 13 Mar 2020 15:20:45 GMT

Method 1: Arrays

Here's a tutorial on using Arrays in SAS
https://stats.idre.ucla.edu/sas/seminars/sas-arrays/

If you need further help please post example data and show what you want as output.

Here are instructions on how to provide sample data as a data step:
https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-data-AKA-generate/ta-p/258712

@knargis160 wrote:

I want to code for multiple variables from level 0 to 2 at once. what is the best wat to do in SAS rather than using if-else statements?

Re: Recoding multiple variables at once

knargis160 — Fri, 13 Mar 2020 15:22:51 GMT

It overwrites the same variable. Is there a way to create new variable (which is recoded) in array statement

Thanks!

Re: Recoding multiple variables at once

PaigeMiller — Fri, 13 Mar 2020 15:30:11 GMT

@knargis160 wrote:

It overwrites the same variable. Is there a way to create new variable (which is recoded) in array statement

Thanks!

Could you please explain the whole problem in sufficient detail (and by showing an example data set and by showing the desired output) that we can understand it? Then we might be able to provide code that meets your needs.

Re: Recoding multiple variables at once

knargis160 — Fri, 13 Mar 2020 15:32:43 GMT

Datalines

ID P1 P2 P3 P4 ….

1 0 1 0 1

2 1 0 0 0

3 0 1 1 1

Output

ID P1 P2 P3 P4

1 2 1 2 1

2 1 2 2 2

3 2 1 1 1

I want to code all "0" to 2

As these are 15 vars like this. I don't want to use if multiple else statement

Re: Recoding multiple variables at once

Reeza — Fri, 13 Mar 2020 15:36:47 GMT

What did you try that overwrites the variable would also help?

Your output shows as it overwriting the original values, but you said that's not what you want above so please clarify.

Re: Recoding multiple variables at once

ed_sas_member — Sat, 14 Mar 2020 08:25:06 GMT

HI @knargis160

You can do this to recode variables in new variables:

data want;
	set have;
	array _arr(*) var1 var2 var3 /* Put the variable names */;
	array _new(3) ; /* Put the number of variables */
	do i=1 to dim(_arr);
		if _arr(i)=0 then _arr(i)=2;
	end;
	drop i;
run;

Best,