st: How to run same code on multiple datasets

["Furner, Zhan" <zhan.furner@ttu.edu>]

Hello all, 

I'm trying to create a do file (see below) that would allow me to run the same code on multiple datasets (the first dataset is yearind19902, then yearind19903...). I think the file runs well for the first dataset because the variable 'ratio' is created correctly in the first dataset. However, Stata stopped executing for the rest of datasets and I got an error message as follows: 
invalid `"yearind19903.dta' 
r(198);


***Begin Code ****

local workdir "C:\xxx\xxx\xxx"
       cd `workdir'
local files: dir "`workdir'" files "*.dta"

foreach aaa of local files {
       use `aaa'
       sort plan
       count if plan<1
       gen n1=r(N)
       count if plan>0
       gen n2=r(N)
       gen ratio=n1/n2 if plan<1 
       replace ratio=1 if missing(ratio)

save `files', replace
}

*** End Code ***


How should I amend my code to fix this problem?

Thank you so much and happy Thanksgiving!

Zhan








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