I have this data:

dat
  month item sales
     1    a    10
     2    c    20
     2    b     5
     3    a     3

As you can see, there are some missings. Not every item is listed in a month since there were no sales. I want to complete the data and fill the missings values in sales with 0.

The result should look like this:

  month item sales
     1    a   10
     1    b   0
     1    c   0
     2    a   0
     2    b   5
     2    c   20
     3    a   3
     3    b   0
     3    c   0

Is there a way to add the missing combinations to a data frame and impute the missings with 0.

structure(list(month = c(1, 2, 2, 3), item = structure(c(2L, 
3L, 4L, 1L), .Label = c("a", "A", "b", "c"), class = "factor"), 
    sales = c(10, 20, 5, 3)), class = "data.frame", row.names = c(NA, 
-4L))

0 Answers