question about making binary variables from an array

[lmyers2]

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 

[Reeza]

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

[Reeza]

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.

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@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 

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[lmyers2 · Accepted solution]

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?

[Reeza]

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?

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@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?

---

[lmyers2]

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!