down_sampling

import numpy as np

click_indices = us[us.click_bool == 1].index
random_indices = np.random.choice(click_indices, len(us.loc[us.click_bool == 1]), replace=False)
click_sample = us.loc[random_indices]

not_click = us[us.click_bool == 0].index
random_indices = np.random.choice(not_click, sum(us['click_bool']), replace=False)
not_click_sample = us.loc[random_indices]

us_new = pd.concat([not_click_sample, click_sample], axis=0)

print("Percentage of not click impressions: ", len(us_new[us_new.click_bool == 0])/len(us_new))
print("Percentage of click impression: ", len(us_new[us_new.click_bool == 1])/len(us_new))
print("Total number of records in resampled data: ", len(us_new))