Create summary table of categorical variables of different lengths

Question

In SPSS it is fairly easy to create a summary table of categorical variables using \"Custom Tables\":

Answer 1

Here is a solution using the freq function of the questionr package (shameless autopromotion, sorry) :

R> lapply(df, freq)
$vs
    n    %
0  18 56.2
1  14 43.8
NA  0  0.0

$am
    n    %
0  19 59.4
1  13 40.6
NA  0  0.0

$gear
    n    %
3  15 46.9
4  12 37.5
5   5 15.6
NA  0  0.0

$carb
    n    %
1   7 21.9
2  10 31.2
3   3  9.4
4  10 31.2
6   1  3.1
8   1  3.1
NA  0  0.0