# Collapse multiple Columns in Pandas in Python # Python program to collapse# multiple Columns using Pandasimport pandas as pd  # sample datan = 3Sample_1 = [57, 51, 6]Sample_2 = [92, 16, 19]Sample_3 = [15, 93, 71]Sample_4 = [28, 73, 31]  sample_id = zip(["S"]*n, list(range(1, n + 1)))  s_names = [''.join([w[0], str(w[1])]) for w in sample_id]  d = {'s_names': s_names, 'Sample_1': Sample_1,      'Sample_2': Sample_2, 'Sample_3': Sample_3,     'Sample_4': Sample_4}  df_1 = pd.DataFrame(d)  mapping = {'Sample_1': 'Result_1',           'Sample_2': 'Result_1',            'Sample_3': 'Result_2',            'Sample_4': 'Result_2'}  df = df_1.set_index('s_names').groupby(mapping, axis = 1).sum()  df.reset_index(level = 0)