Analyzing the Content of a Categorical Variable

Now that we've got a good feel for the kind of information contained in the online retail dataset, we want to dig a little deeper into each of its columns:

import pandas as pd
file_url = 'https://github.com/PacktWorkshops/The-Data-Science-Workshop/blob/master/Chapter10/dataset/Online%20Retail.xlsx?raw=true'
df = pd.read_excel(file_url)

For instance, we would like to know how many different values are contained in each of the variables by calling the nunique() method. This is particularly useful for a categorical variable with a limited number of values, such as Country:

df['Country'].nunique()

You should get the following output:

38

We can see that there are 38 different countries in this dataset. It would be great if we could get a list of all the values in this column. Thankfully, the pandas package provides a method to get these results: unique():

df['Country'].unique()

You...