Evaluate all array elements using 'do loop' to create a single variable

gkirkner — Thu, 21 Mar 2019 21:27:24 GMT

Hello,

I'm trying to use an array and 'do loop' to create a new summary variable based on the evaluation of all the array variables, but the result I get is based on only the last variable in the array. Basically, I'm trying to evaluate 6 variables to determine the value of 1 new variable.

I have 6 genetic test status result variables: 'OverallTestStatus_Result_1' through 'OverallTestStatus_Result_6', and they are coded -1="True Negative; 0="Variant"; and 1="True Positive". My data has 1 record per Subject.

If a Subject has a "True Positive" (code 1) for ANY of their 6 result variables, then they should get a value of 1 (Positive) for the new summary variable 'genetic_test_summary'.

If a Subject doesn't have a "True Positive" (code 1) for ANY of their 6 result variables, but they do have a "Variant' (coded 0) for ANY of their 6 result variables, then they should get a value of 0 (Variant) for the new variable 'genetic_test_summary'.

And finally, if a Subject has a "True Negative" (code -1) for ALL of their 6 result variables, then they should get a value of -1 (Negative) for the new summary variable 'genetic_test_summary'.

I thought that using 'else if' would work to address the ANY vs. ALL requirement/condition for the different summary variable value scenarios, but it does not.

Can this be done with a 'do loop'? How do I evaluate every element of the array, not just the last, and is there a way to evaluate different array elements with 'AND' or 'OR'?

A snip of my code is below, but it doesn't work. If a subject has a "True Positive" (code 1) for their first 5 result variables, and the 6th result variable is a "Variant" (code 0), then the summary variable 'genetic_test_summary' gets coded 0 (Variant).

/* Creating a summary variable (for anyone tested)       */
/* to denote  "Positive" (any overallteststatus that     */
/* includes a "True positive"); and if all true negative */
/* then it would be coded be as "Negative"; if there is  */
/* a variant, would be "variant" (except if there was    */
/* also a positive test result, then this would trump    */
/* "variant").                                           */

array OverallTestStatusArr {6} OverallTestStatus_Result_1 OverallTestStatus_Result_2 OverallTestStatus_Result_3
                               OverallTestStatus_Result_4 OverallTestStatus_Result_5 OverallTestStatus_Result_6;

do i = 1 to 6 while(OverallTestStatusArr{i} ne .);
       if OverallTestStatusArr{i}=1 then genetic_test_summary=1; /* Positive */
  else if OverallTestStatusArr{i}=0  then genetic_test_summary=0; /* Variant */
  else if OverallTestStatusArr{i}=-1 then genetic_test_summary=-1; /* Negative */
end;
drop i;

Thanks.

Re: Evaluate all array elements using 'do loop' to create a single variable

Astounding — Fri, 22 Mar 2019 01:02:17 GMT

You have to decide what to do if there might be missing values in the data. Other than that, a single statement should compute the result you are asking for:

genetic_test_summary = max(of Overall_Test_Status_Result_: );

This assumes that the six variables you mention are the only ones with names that begin with "Overall_Test_Status_Result_").

Re: Evaluate all array elements using 'do loop' to create a single variable

gkirkner — Fri, 22 Mar 2019 13:58:26 GMT

Thanks, Astounding! This worked, and I was apparently way overthinking this.

topic Evaluate all array elements using 'do loop' to create a single variable in SAS Programming

Evaluate all array elements using 'do loop' to create a single variable

Re: Evaluate all array elements using 'do loop' to create a single variable

Re: Evaluate all array elements using 'do loop' to create a single variable