import numpy as np
import pandas as pd
import matplotlib
import matplotlib.pyplot as plt
plt.style.use('ggplot')
%matplotlib

url = 'https://archive.ics.uci.edu/ml/machine-learning-databases/credit-screening/crx.data'
data = pd.read_csv(url, header=None, na_values='?')
data.shape
data.columns = ['A' + str(i) for i in range(1, 16)] + ['class']

categorical_columns = [c for c in data.columns if data[c].dtype.name == 'object']
numerical_columns   = [c for c in data.columns if data[c].dtype.name != 'object']
print(categorical_columns)
print(numerical_columns)
for c in categorical_columns:
    print(data[c].unique())