I have a large panel dataset that looks as follows.
input id age high weight str6 daily_drink
1 10 110 35 water
1 10 110 35 coffee
1 11 120 38 water
1 11 120 38 coffee
1 12 130 50 water
1 12 130 50 coffee
2 11 118 31 water
2 11 118 31 coffee
2 11 118 31 milk
2 12 123 38 water
2 12 123 38 coffee
2 12 123 38 milk
3 10 98 55 water
3 11 116 36 water
3 12 129 39 water
4 12 125 40 water
end
However, I would like to use stata to keep objects with complete 10, 11, and 12 age. Looks like this.
id age high weight daily_drink
1 10 110 35 water
1 10 110 35 coffee
1 11 120 38 water
1 11 120 38 coffee
1 12 130 50 water
1 12 130 50 coffee
3 10 98 55 water
3 11 116 36 water
3 12 129 39 water
However, all the rows are without missing data, so I cannot simply delete the row with missing data. Is there any way to do it? Any suggestion will help. Thanks in advance.
You can use bysort and egen for this. Something along the lines of
bysort id: egen has10 = total(age==10)
bysort id: egen has11 = total(age==11)
bysort id: egen has12 = total(age==12)
keep if (has10 != 0) & (has11 != 0) & (has12 != 0)
should work (untested). See help egen for more info. Install gtools if you have very large data (ssc install gtools) and then replace egen by gegen.