How to create loop for every month updated 12 months data?

[sasuser1031]

I have master data of 12 months. I am caluclating value of one varible based on previous months values. I have calculated Feb values based on Jan values. Now, I want to calculate March value based on Jan and New Feb values; April value based on Jan, New Feb, New March values and so on...The new monthly value has to go in master dataset everytime. I have to use updated master file everytime. 

Can you please help me to write the loop? 

[Shmuel]

The answer to your question depends on your dataset format.

Please provide a sample data with the 12 month in it.

[sasuser1031]

I have caluclated it  for Feb and  applied back on master dataset I am just trying to iterative process for 12 months.  

[PaigeMiller]

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@sasuser1031 wrote:

I have caluclated it  for Feb and  applied back on master dataset I am just trying to iterative process for 12 months.  

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This completely avoids answering the question.

We still don't know what the calculation is that you are doing.

And you haven't provided an example, as was also requested.

[PaigeMiller]

Now, I want to calculate March value based on Jan and New Feb values;

Explain. What is the calculation? Sum? Average? Delta? Time series prediction? arc-cosine?

[sasuser1031]

I have caluclated it  for Feb and  applied back on master dataset I am just trying to iterative process for 12 months.  

[Shmuel]

Does this answers your question:

do i = 1 to 12;
    if i > 2 then do j=1 to i;
       <calculate month(j) depending on month(i)>
   end;
end;