Count unique groups/panels within a dataset

[Ruxy Benedict]

Hello,

This is my first time posting on Statalist and I am looking for some help with code. I am using Stata 17.0 on Windows.

I have a dataset where I would like to count for each country (hv000), the total number of IDs (team2), that have a certain characteristic (whz==0).
In the dataset

• whz is a binary variable 1/0
• the team IDs are not unique to each country and the number of teams per country vary
• there are some observations where the characteristic is missing, but for my purposes I can ignore missing

Below is a random example from the datatset. And for example I would count for "ET7a" 5 teams with my characteristic, "SN6a" would be 2 teams etc.

* Example generated by -dataex-. For more info, type help dataex
clear
input str4 hv000 float(team2 whz)
"ET7a" 1502 0
"ET7a" 3302 0
"ET7a" 2002 0
"ET7a" 2602 0
"ET7a"  402 0
"ET7a" 1902 .
"SN6a"  916 .
"SN6a"  914 0
"SN6a"  904 0
"SN6b"   20 0
"SN6c"   10 0
"SN6c"   30 0
"SN6d"   20 0
"SN6d"   20 0
"SN7a"  100 0
"SN7a"  170 0
"SN7a"  100 0
"SN7a"  110 0
"SN7b"  120 0
"SN7b"  120 0
end