Frequency of values per column in table

Question

What is a good way to get the independent frequency counts of multiple columns using dplyr? I want to go from a table of values:

# A tibble: 7          


        

Answer 1

Using tabulate in base R:

apply(df,2,function(x) tabulate(x)[min(df):max(df)])

#     a  b c  d
#[1,] 2  0 2  1
#[2,] 1  4 2  0
#[3,] 2  2 0  6
#[4,] 0  1 2 NA
#[5,] 2 NA 1 NA