Multiple variables with null values

[dikshar]

I am working with a dataset that has a about 10 variables for different treatments. If a patient underwent a particular treatment, then that treatment's variable has a date and the rest of the treatment variables are null. I want to make a new variable so that whichever treatment a patient underwent, the corresponding value is posted to a new variable. 

Example:

Obs  TrtA     TrtB3           TrtGh     TrtE8

1         .       01/01/2019       .          .

2         .             .           01/04/2019   .

3         .       01/12/2019       .          .

I want the output to look like:

Obs         Trt_date

1              01/01/2019

2              01/04/2019              

3              01/12/2019

I am completely stuck after trying multiple if statements, treating each variable individually and together, and nothing is working. Please help!

[Reeza · Accepted solution]

Have you tried the COALESCE() function?

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@dikshar wrote:

I am working with a dataset that has a about 10 variables for different treatments. If a patient underwent a particular treatment, then that treatment's variable has a date and the rest of the treatment variables are null. I want to make a new variable so that whichever treatment a patient underwent, the corresponding value is posted to a new variable. 

Example:

Obs  TrtA     TrtB3           TrtGh     TrtE8

1         .       01/01/2019       .          .

2         .             .           01/04/2019   .

3         .       01/12/2019       .          .

I want the output to look like:

Obs         Trt_date

1              01/01/2019

2              01/04/2019              

3              01/12/2019

I am completely stuck after trying multiple if statements, treating each variable individually and together, and nothing is working. Please help!

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[ballardw]

If your description that only one of the trt variables has value then this should work:

data want;
  set have;
  array t{10} trtb3 trtgh trte8 <finish the list>;
  trt_date = max( of t(*));
  format trt_date mmddyy10.;
run;