Looping over mean

[Maya Moore]

Hi Stata Community,

I hope you are all doing well! I got a (hopefully) quick question relating to how to loop over a mean. In particular, I got a variable that is called change1m_ that I would like to take the mean of if the dummy variable called flag equals 1. Without a loop, this should be

mean change1m_ if flag ==1

Now my question is:
(a) how do I loop over this for different year and month combinations and
(b) how do I save the respective value so I can import it into Excel? Please see my (unsuccessful) attempt below:

putexcel set Trimmed_PCE.xlsx, sheet(data) replace
putexcel A1 = "Year"
putexcel B1 = "Month"
putexcel C1 = "Trimmed mean"
local row = 2
forvalues y = 2021(1)2021 {
   forvalues m = 1(1)12{
   preserve
   keep if year==`y' & month==`m'
   sort change1m_
   gen cum`y'`m' = sum(weight)
   generate flag`y'`m' = 1
   replace flag`y'`m' = 0 if cum`y'`m'>=69 | cum`y'`m'<=25
   mean change1m_ if flag ==1
   putexcel A`row' = `y'
   putexcel B`row' = `m'
   putexcel C`row' = 
   local ++row
    restore
    }
}

The data in the data editor basically look like this

category	change1m_	year	month	day	weight_	modate	cum	flag
CPIVGRAPIndex	-31.038	2021	9	30	0.186	2021m9	0.186	0
CPIVWOAPIndex	-26.7469	2021	9	30	0.884	2021m9	1.07	0
CPIVCFVEIndex	-1.5016	2021	9	30	0.148	2021m9	18.76933	1
CPIVABHOIndex	-0.65833	2021	9	30	0.562	2021m9	19.33133	1
CPIVCHICIndex	-0.32432	2021	9	30	0.279	2021m9	19.61033	1
CPIVEGECIndex	-0.28941	2021	9	30	0.351	2021m9	19.96133	1
CPIVFUOIIndex	58.14851	2021	9	30	0.096	2021m9	98.8795	0
CPIVBEVEIndex	74.84962	2021	9	30	0.515	2021m9	99.3945	0

Thank you so much!

[alejoforero]

To extract that value after an estimation command like mean use

ereturn list

to see the output in terms of macros, scalars and matrices.
In this case what you want is:

loc mean=e(b)[1,1]
di `mean'
putexcel C`row' = `mean'

[Maya Moore]

Hi Alejoforero - it worked perfectly. Thanks!