I have multiple csv files in the same folder with all the same data columns,
20100104 080100;5369;5378.5;5365;5378;2368 20100104 080200;5378;5385;5377;5384.5;65
Instead of using a list just use DataFrame's append.
df = pd.DataFrame() for file_ in all_files: file_df = pd.read_csv(file_,sep=';', parse_dates=[0], infer_datetime_format=True,header=None ) file_df['file_name'] = file_ df = df.append(file_df)