Hi statalists,

I have two variables, period and company. Period is the accumulative number of quarters starting from 2004. So, 1 is the first quarter of 2004, and 5 is the first quarter of 2005. I would like to know how to keep for each year only the last quarter, namely 4,8,12,16,20... is there a better code than do "keep if period == 4|period == 8|period == 12|period == 16|period == 20|period == 24"?

Thank you!!
Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(period company)
 1 2
 1 2
 1 2
 1 2
 1 2
 1 2
 1 2
 2 2
 2 2
 2 2
 2 2
 2 2
 3 2
 3 2
 3 2
 3 2
 3 2
 3 2
 4 2
 4 2
 4 2
 4 2
 4 2
 4 2
 5 2
 5 2
 5 2
 5 2
 5 2
 5 2
 5 2
 6 2
 6 2
 6 2
 6 2
 6 2
 6 2
 6 2
 7 2
 7 2
 7 2
 7 2
 7 2
 7 2
 8 2
 8 2
 8 2
 8 2
 8 2
 8 2
 8 2
 8 2
 8 2
 9 2
 9 2
 9 2
 9 2
 9 2
 9 2
 9 2
 9 2
 9 2
 9 2
 9 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
10 2
11 2
11 2
11 2
end