1. 데이터 준비import numpy as npimport pandas as pddata = { 'A': [1, 2, np.nan, 4, 5, 100, 1, 2, 2, 4, '1', '2', '3', '4', '5', 10, 20, 30, 40, 50], 'B': [5, np.nan, np.nan, 8, 10, 60, 10, 20, 20, 40, '10', '20', '30', '40', '50', 5, 4, 3, 2, 1], 'C': [1, 2, 3, 4, 5, 5, 100, 200, 200, 400, 100, 200, 300, 400, 500, 1, 2, 3, 4, 5], 'D': [np.nan, np.nan, 3, 3, 3, 5, 5, 5, 5, 5, np.nan, np.na..