Matrix by group of observations

[Pide Lun]

Dear Statalisters,

I have a panel data of 48 countries, each for 28 years. I want to create 48 matrixes corresponding to each country at once. So each matrix has 28 x 1 dimension. I have tried to use "forvalues", but it does not seem to work. See my codes below:

forvalues i=1/48{
mkmat undata if id==`i', matrix(y)
}

I am very new to Stata programming.

Thanks very much for your help.

[Jesse Wursten]

The reason your code didn't work is that you were creating the matrix y for the first country and then replaced it for each following country. If you replace matrix(y) by matrix(y`i') it should work. Alternatively, use the code snippet below, it will work even if your countries are not nicely defined from 1/48 (and will accept strings even).

levelsof <country>, local(countries)
foreach <country> of local countries {
     mkmat undata if <country> == `county', matrix(matrix`country')
}

replace <country> by the name of your country variable