The apply() Method

Like the series, the DataFrame has an apply method. As with Series, we should be wary of using the apply method in DataFrames. More specifically, if we’re dealing with numbers, we might want to see if we can operate in a vectorized way.

Also, keep in mind that a DataFrame is two-dimensional. So rather than applying a function to a single value, when we call apply on a DataFrame, we work on a whole row ...