# Help with matrix and loop Classic List Threaded 1 message Reply | Threaded
Open this post in threaded view
|

## Help with matrix and loop

 This post has NOT been accepted by the mailing list yet. Hi I hope you will understand my problem. I wrote this code ```matrix A=J(17,8,0) forval i=1/17 { forval j=0/7 { quietly summarize var8 if branch== `i' & class== `j' [iw=expansion] matrix A[`i' , `j'+1] = r(sum_w) } }```The matrix A has 17 rows and 8 columns because branch starts from 1 to 17 and class from 0 to 8. So, i'm storing the r(sum_w) for every match. But know i need to expand the quietly summarize var8 if branch== `i' & class== `j' [iw=expansion] to quietly summarize var8 if branch== `i' & class== `j' area=`iregion' [iw=expansion] with area, a variable designing areas in numbers that goes from 1 to 15. But i don't know how to store the values in the matrix. I thought of generating 15 matrices names, and inserting a forval iregion=1/15, but i didn't work. Can you guide me on this? Thanks for your time and interest.