user_id  item_id  rating  timestamp
0      196      242       3  881250949
1      186      302       3  891717742
2       22      377       1  878887116
3      244       51       2  880606923
4      166      346       1  886397596

MyCF.train_data_matrix = numpy.zeros((n_users, n_items))
for line in MyCF.train_data.itertuples():
    MyCF.train_data_matrix[line[1] - 1, line[2] - 1] = line[3]

matrix[user_id][item_id]=rating