Calculate proportion of positives values by group

Question

With this dataframe:

table <- \"
    trt rep ss  d1  d4  d5  d6  d7
    1   1   1   0   0   0   0   0
    1   1   2   0   0   0   0   0
    1   1   3   0          


        

Answer 1

Using data.table, something like this:

library(data.table)
d <- data.table(d)
d[,lapply(.SD,function(x) sum(x>0,na.rm=T)/sum(!is.na(x))),
  .SDcols=grep("^d",names(d),val=T),
   by=trt]

   trt d1        d4        d5        d6        d7
1:   1  0 0.2222222 0.4444444 0.5555556 0.5555556
2:   2  0 0.0000000 0.0000000 0.3750000 0.5000000