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I have a data.table object as follows:

> ans
        race smoking_status    N
 1:    Asian          Never  255
 2:    Asian         Former  130
 3:    Asian        Current    9
 4:    Black          Never  421
 5:    Black         Former  257
 6:    Black        Current  215
 7: Hispanic        Current  184
 8: Hispanic          Never  910
 9: Hispanic         Former  525
10:    White          Never 2955
11:    White         Former 3109
12:    White        Current 1030

> class(ans)
[1] "data.table" "data.frame"

I want to get the number of smokers by race, and the proportions of never, former and current smokers, also by race. How do I do that?

dapple-putt-poultry
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  • `ans[, .(total = sum(N)), by = .(race)]` and `ans[, .(total = sum(N)), by = .(smoking_status)][, proportion := total / sum(total)][]` – r2evans Dec 10 '22 at 01:42

0 Answers0