Calculate export times using custom data

[Carle Tong]

clear
input str10 company_name str3 country int year
"3Mcompany"  "USA" 2002
"3Mcompany"  "USA" 2002
"3Mcompany"  "USA" 2003
"3Mcompany"  "USA" 2004
"3Mcompany"  "USA" 2005
"3Mcompany"  "USA" 2007
"3Mcompany"  "USA" 2008
"3Mcompany"  "USA" 2009
"3Mcompany"  "USA" 2010
"3Mcompany2" "DEU" 2003
"3Mcompany2" "DEU" 2003
"3Mcompany2" "DEU" 2004
"3Mcompany2" "DEU" 2005
"3Mcompany2" "DEU" 2007
"3Mcompany2" "DEU" 2009
"3Mcompany2" "FRA" 2003
"3Mcompany2" "FRA" 2004
"3Mcompany2" "FRA" 2005
end

The original data format.

And the finally data format like this pacture.

Explanation:
total_times:company A exist in country B of different year
period_times: If year in 2002 to 2005 without interruption is 1 period.
first_period_times:How many times in first period_times.
How to use stata code to achieve it.

[Phil Bromiley]

Welcome to Stata list. You will increase your chances of useful answer by following the FAQ for asking questions – provide Stata code in code delimiters, readable Stata output, and sample data using dataex.

I simply don't understand what you are trying to do. If I guess at what you want, this is what I get. At least for total times by year, you can use
bysort company year: egen times=count(year)

The year within the brackets is simply to give something that Stata can count.

You probably can do the period times pretty much the same way just adding an if statement to limit the sample used to those years.

bysort company year: egen times=count(year) if year<2006