I have one dataset with a ID variable and three different variables, age, height, and weight).
ID age height weight
1 20 . .
2 21 . .
3 25 . .
1 . 160 .
2 . 165 .
3 . 170 .
1 . . 61
2 . . 80
3 . . 71

I would like to remove missing values and make a dataset horizontal.
ID age height weight
1 20 160 61
2 21 165 80
3 25 170 71
Since I have more than 10,000 IDs and 10 variable, I could not do it manually. Please help me solve this problem. Thanks!