## CONDITIONAL SELECTION OF COMBINATIONS OF THREE VARIABLES USING ARRAY

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# CONDITIONAL SELECTION OF COMBINATIONS OF THREE VARIABLES USING ARRAY

I have to select patients who has specific combinations of conditions as following:

1. patients with both P2 and the Pa;

OR

2. patients with both the P3 and the Pa;

Patients must have P2 and P3 with the Pa to be eligible. Simply put: P2+Pa, P3+Pa, P2+P3+Pa combinations are acceptable.

``````data combinations; set have;
array diagnosis[*] condition othercondition_1-othercondition_24;
do i = 1 to dim(diagnosis);
if diagnosis[i] in ('P2','P3') then x=1;
if diagnosis[i] in ('Pa')      then y=1;
if x=1 and y=1 then output;
end;
drop i;
run;``````

However, resulting data "combinations" has an information for single subject (row) repeated 20 times. Very strange. Any idea why that happened?

LOG:

There were 95560 observations read from the data set WORK.HAVE.
NOTE: The data set WORK.COMBINATIONS has 20 observations and 66 variables.

Using SAS 9.4.

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‎06-19-2017 09:58 PM
Super User
Posts: 5,718

## Re: CONDITIONAL SELECTION OF COMBINATIONS OF THREE VARIABLES USING ARRAY

A simple solution:  move the OUTPUT statement.  Instead of coding it inside the DO loop, move it to after the END statement.

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Super User
Posts: 20,730

## Re: CONDITIONAL SELECTION OF COMBINATIONS OF THREE VARIABLES USING ARRAY

Use WHICHC() to create flags for each of your three variables and then use those variables to do your conditioning.

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Solution
‎06-19-2017 09:58 PM
Super User
Posts: 5,718

## Re: CONDITIONAL SELECTION OF COMBINATIONS OF THREE VARIABLES USING ARRAY

A simple solution:  move the OUTPUT statement.  Instead of coding it inside the DO loop, move it to after the END statement.

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