Character variables are being converted to numeric, don't understand why.

[megsredl]

I have a list of diagnostic codes in variables dx1-dx9 for each observation. I'm trying to extract the first diagnostic code that matches a specified subset for each observation. Here's the basic structure of my data:

data test;
	input dx1 $ dx2 $ dx3 $ dx4 $ dx5 $ dx6 $ dx7 $ dx8 $ dx9 $;
	datalines;
		D2002 O2829 V1002 T2000 W2018 . . . .
		B1080 V1001 S400X R2910 44323 I1088 FB372 X3007 A5850
		M5992 R6602 U2710 S400X D0412 V1002 C4010 . .
		;
run;

This is the code I wrote: 

data pwid.test;
	length first_dx $6;
	set pwid.test;
	array dxnum[9] dx1-dx9;
	do i = 1 to 9;
		if dxnum[i] not in ("V1001", "V1002", "S400X") then continue;
		else first_dx=dxnum[i] and leave;
	end;
run;

I'm getting a message for my "else" line that character values have been converted to numeric values and numeric values have been converted to character values, then I get an error message saying "invalid numeric data" (see screenshot). As far as I can tell everything should be a character variable, so I'm not sure why anything is getting converted to numeric. What's causing this issue? If there's a better way to write this code I'd appreciate that as well. Thank you!

[novinosrin]

Not sure your exact objective, can i assume this is what you perhaps want?

data test1;
	length first_dx $6;
	set test;
	array dxnum[9] dx1-dx9;
	do i = 1 to 9;
		if dxnum[i] not in ("V1001", "V1002", "S400X") then continue;
		else  first_dx=dxnum[i];
	end;
run;

[megsredl]

I'm trying to set first_dx to the first matching diagnostic code listed in dx1-dx9. In the above example, that would be V1002 for obs 1, V1001 for obs 2, and S400X for obs 3. I think your code keeps running the do loop even after it finds a match, so first_dx is set to the last matching code.

[Astounding]

I would recommend this variation:

	do i = 1 to 9 until (first_dx > ' ');
		if dxnum[i] in ("V1001", "V1002", "S400X") then 
		first_dx=dxnum[i];
	end;

[PaigeMiller]

Please read the entire log from this. Your problem is at line 189, column 23. What is there? At that location is a NUMERIC variable named LEAVE. You can't assign the value DXNUM[i] AND LEAVE to FIRST_DX, because DXNUM[i] is charcter and LEAVE is numeric and so the statement DXNUM[i] AND LEAVE cannot be evaluated.

[megsredl]

Thanks, I figured that might be my problem. How can I exit the do loop at that point since leave doesn't work?

[andreas_lds · Accepted solution]

Try:
else do;
first_dx=dxnum[i];
leave;
end;

[megsredl]

Thank you so much!

[Tom]

Forget about LEAVE and CONTINUE. 

Tell the DO statement what criteria to use to end the looping.

data pwid.test;
  set pwid.test;
  array dxnum[9] dx1-dx9;
  length first_dx $6;
  do i = 1 to 9 until(not missing(first_dx));
    if dxnum[i] in ("V1001", "V1002", "S400X") then first_dx=dxnum[i];
  end;
run;

[megsredl]

Thanks for the help, this syntax is much more straightforward.