1 先把一行直接读成一个小单元格 2 对于一个单元格子，用split(逗号)分开，横向expanding拓展很多col，这样col[0]就是instrument了
# Input
1,2,3,4,5
1,2,3,4,5,6
,,3,4,5
1,2,3,4,5,6,7
,2,,4
# Output (DataFrame)
0 1 2 3 4 5 6
0 1 2 3 4 5 None None
1 1 2 3 4 5 6 None
2 3 4 5 None None
3 1 2 3 4 5 6 7
4 2 4 None None None
import pandas as pd
df = pd.read_csv('Test.csv', header=None, sep='\n')
df = df[0].str.split(',', expand=True)
# ... do some modifications with df
