Appending Frequency Tables - With Missing Values

Question

The goal is to produce a frequency table of all my selected variables (about reading habits for 4 Newspapers) which in essence have the same possible values:

1=         


        

Answer 1

You could use mtabulate from qdapTools

library(qdapTools)
t(mtabulate(list(a,b,d,e)))
#  [,1] [,2] [,3] [,4]
#0    0    2    5    0
#1    2    1    0    0
#2    2    2    2    0
#3    4    3    2   10
#4    2    2    1    0

Or

t(mtabulate(data.frame(a,b,d,e)))
#  a b d  e
#0 0 2 5  0
#1 2 1 0  0
#2 2 2 2  0
#3 4 3 2 10
#4 2 2 1  0