Since the dataset was in a CSV file, after reading it into the R environment, it got stored as a data frame. In this recipe, you will use the matrix operation, so you need to convert the data frame into a matrix. That’s why, in the Getting ready section, the data frame has been converted into a matrix using the as.matrix() function.

In the next step, two functions were written, one using a for loop to calculate the frequency of each column in the dataset and also all possible pair-wise frequencies, and the other function also did the same task but it was implemented without using any loop. The second function uses a certain logic to calculate the frequency and cross-frequency, that is, if all of the variables in a dataset are binary, then if you multiply the transpose of the data matrix with the data matrix itself, it will give the desired results.