Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input int(id dum1 dum2 dum3 dum4) float (price newprice )
1 1 0 0 0 20   20
1 0 1 0 0 30 32.5
1 0 0 1 0 25   25
1 0 0 0 1 20 22.5
1 0 0 0 1 25 22.5
1 0 1 0 0 35 32.5
1 0 1 0 0 32.5 32.5
end

Hi, in the above data, I want to create newprice as the mean of price for each category of dummies taking value 1.

for example, newprice takes value 22.5 ( average of 20 and 25) where dum4 takes value 1.

Similarly, newprice takesvalue 32.5 ( average of 30, 35 and 32.5) where dum2 takes value 1.

How should I go about creating newprice ?

Thanks.