topic Re: question about making binary variables from an array in SAS Data Management

question about making binary variables from an array

lmyers2 — Mon, 17 Sep 2018 18:05:19 GMT

Hello,

I have a simple question about making binary variables from an array. Sample data and code are below. I believe my code will categorize Case 3 as 'first' and then it doesn't keep reading to SERVICE_EXTENDER2 to also include it as having a 'second.' I tried using "else" in the code but that didn't help. I'm sure there's an easy solution...

Case SERVICE_EXTENDER1 SERVICE_EXTENDER2 SERVICE_EXTENDER3 SERVICE_EXTENDER4
1 first
2 second
3 first second
4 first

data want; set have;
array SERVICE_EXTENDER [4] $ SERVICE_EXTENDER1-SERVICE_EXTENDER4;
do z=1 to 4;
if SERVICE_EXTENDER [z]='first' then new_variable='first';
if SERVICE_EXTENDER [z]='second' then new_variable='second'; 
end;
run;

proc freq data=want; tables new_variable*case_control / missing; run;

Thanks

laura

Re: question about making binary variables from an array

Reeza — Mon, 17 Sep 2018 18:21:57 GMT

What are you trying to do here? It's not clear what you want as output.

Re: question about making binary variables from an array

Reeza — Mon, 17 Sep 2018 18:30:58 GMT

You likely only need WHICHC.

First_Flag = whichc('first', of service_extender1-service_extender4)>0;
Second_Flag = whichc('second', of service_extender1-service_extender4)>0;

Note that you do not need a loop or array declaration unless you really want to.

@lmyers2 wrote:

Hello,

I have a simple question about making binary variables from an array. Sample data and code are below. I believe my code will categorize Case 3 as 'first' and then it doesn't keep reading to SERVICE_EXTENDER2 to also include it as having a 'second.' I tried using "else" in the code but that didn't help. I'm sure there's an easy solution...

Case SERVICE_EXTENDER1 SERVICE_EXTENDER2 SERVICE_EXTENDER3 SERVICE_EXTENDER4
1 first
2 second
3 first second
4 first
data want; set have;
array SERVICE_EXTENDER [4] $ SERVICE_EXTENDER1-SERVICE_EXTENDER4;
do z=1 to 4;
if SERVICE_EXTENDER [z]='first' then new_variable='first';
if SERVICE_EXTENDER [z]='second' then new_variable='second'; 
end;
run;

proc freq data=want; tables new_variable*case_control / missing; run;
Thanks

laura

Re: question about making binary variables from an array

lmyers2 — Mon, 17 Sep 2018 18:56:49 GMT

Thanks so much for responding. What I'd like is for case 3 to be counted in both new_variable='first' and new_variable='second,' since the array contains both. Is there a way to do this with the array syntax I have, maybe without the do loop?

Re: question about making binary variables from an array

Reeza — Mon, 17 Sep 2018 19:09:22 GMT

Show your expected output and it'll be clear (to me) what needs to change. Right now, you're creating a single variable that indicates first or second, but your data clearly indicates that both can occur. So what do you want to do when that case is encountered?

@lmyers2 wrote:

Thanks so much for responding. What I'd like is for case 3 to be counted in both new_variable='first' and new_variable='second,' since the array contains both. Is there a way to do this with the array syntax I have, maybe without the do loop?

Re: question about making binary variables from an array

lmyers2 — Fri, 21 Sep 2018 22:21:50 GMT

You're right. I don't need the do loop. I just did a data step and searched within the array and it was much easier!