Sub Value and Add new column pandas
问题 I am trying to read few files from a path as extension to my previous question The answer given by Jianxun Definitely makes sense but I am getting a key error. very very new to pandas and not able to fix error. Note: I use Python 2.7 and Pandas 0.16 File_1.csv Ids,12:00:00 2341,9865 7352,8969 File_2.csv Ids,12:45:00 1234,9865 8435,8969 Master.csv Ids,00:00:00,00:30:00,00:45:00 1234,1000,500,100 8435,5243,300,200 2341,563,400,400 7352,345,500,600 Programs: import pandas as pd import numpy as