Combine multiple columns into one

[Yuxi Chen]

Hi all,

If there is a loop like following:

forv y = 2009/2012 {
forv p = 1/20 {
    egen `y'_`p' = mean(var) if year == `y' & portfolio == `p'
}
}

is there a way to combine `y'_`p' into a single column?

Thank you.

[daniel klein]

If I understand this correctly, it would be simpler if there was no such loop in the first place.

bysort year portfolio : egen mean = mean(var)

Note that `y'_`p' cannot be a valid variable name because both `y' and `p' hold numbers and variable names cannot start with numbers.

Best
Daniel

[Yuxi Chen]

ah yes indeed, bys could do the trick..I felt stupid to ask this, thank you Daniel.

[daniel klein]

I felt stupid to ask this

Do not. Chances are, you are not the only one having this problem.

Best
Daniel