Replacing all missing values in R data.table with a value

Question

If you have an R data.table that has missing values, how do you replace all of them with say, the value 0? E.g.

aa = data.table(V1=1:10,V2=c(1,2,2,3,3,3,4,4,         


        

Answer 1

Nothing unusual here:

tt[is.na(tt)] = 0

..will work.

This is somewhat confusing however given that:

tt[is.na(tt)]

...currently returns:

Error in [.data.table(tt, is.na(tt)) : i is invalid type (matrix). Perhaps in future a 2 column matrix could return a list of elements of DT (in the spirit of A[B] in FAQ 2.14). Please let datatable-help know if you'd like this, or add your comments to FR #1611.