Loop

Hello Stata-Community,
I have a varlist called 'surgery' containing numbers from 1-5.

I would like to compute calculations of the dataset foreach values from 1-5 with dropping the other values and save the results in an exelfile on separate sheets.
I thought about coding something like this:

Code:

save final_set.dta, replace 

foreach var of varlist surgery {
            keep if surgery ==1/2/3/4/5
            here come many calculations.....
            here come many calculations.....
            here come many calculations.....
            putexcel set final_results.xls, sheet("final_results_surgery_1/2/3/4/5") modify
            clear all
            use final_set.dta
            }

Could somebody help me with loop?
In the first loop I want to keep only surgery==1 and save the results in "final_results_surgery_1"
In the second loop I want to keep only surgery==2 and save the results in "final_results_surgery_2"
.....