pandas.factorize on an entire data frame

Question

pandas.factorize encodes input values as an enumerated type or categorical variable.

But how can I easily and efficiently convert many columns of a data frame? What

Answer 1

I would like to redirect my answer: https://stackoverflow.com/a/32011969/1694714

Old answer

Another readable solution for this problem, when you want to keep the categories consistent across the the resulting DataFrame is using replace:

def categorise(df):
    categories = {k: v for v, k in enumerate(df.stack().unique())}
    return df.replace(categories)

Performs slightly worse than the example by @jezrael, but easier to read. Also, it might escalate better for bigger datasets. I can do some proper testing if anyone is interested.