Empty list conditional

I get a list from reading the columns of an excel file, I need to validate if a column is in the list, if not then create it empty, but the conditional is not working, I know for a fact that 'City' is missing so I'm expecting it to be created and is not.

files = os.listdir(input_path)  files_xlsx = [f for f in files if f[-5:] == ".xlsx"]    df = pd.DataFrame()    for f in files_xlsx:      wb = load_workbook(input_path + "\\" + f, read_only=True)      if 'New Leads' in wb.sheetnames:          df = pd.read_excel(input_path + "\\" + f, sheet_name="New Leads")          colre = [col for col in df.columns if "Email" in col]          for eo in colre:              df.rename(columns={eo: eo.replace(' ','').replace('*','').replace('**','') for eo in colre}, inplace=True)          dtcol = [col for col in df.columns if "FIRST NAME" in col.upper()]          for ex in dtcol:              df.rename(columns={ex: "First Name"}, inplace=True)          dtcol = [col for col in df.columns if "LAST NAME" in col.upper()]          for ex in dtcol:              df.rename(columns={ex: "Last Name"}, inplace=True)  

NOT WORKING PIECE OF CODE

        dtcol = [col for col in df.columns if "CITY" in col.upper()]          for ex in dtcol:              if len(dtcol)==0:                  df['City'] = NaN              else:                  df.rename(columns={ex: "City"}, inplace=True)  

END OF NOT WORKING PIECE OF CODE

        dtcol = [col for col in df.columns if "COMPANY NAME" in col.upper()]          for ex in dtcol:              df.rename(columns={ex: "*** Company"}, inplace=True)          if "SOURCE" in cols:              df['Email'].replace('', np.nan, inplace=True)              df.dropna(subset=['Email'], inplace=True)              if df.dtypes['SOURCE'] != 'float':                  df.dropna(how = 'all')                  df['File'] = f                  if df.SOURCE.map(lambda x: len(x)).max() <= 10:                      df = pd.merge(df, df_ac[["SOURCE", "Lead Source", "Lead Category"]], on="SOURCE", how='left')                      del df['SOURCE']                      df.rename(columns={"Lead Source": "SOURCE"}, inplace=True)                  else:                      df.rename(columns={"SOURCE": "Lead Source"}, inplace=True)                      df = pd.merge(df, df_ac[["Lead Source", "Lead Category"]], on="Lead Source", how='left')                      df.rename(columns={"Lead Source": "SOURCE"}, inplace=True)                  df_xlsx = pd.concat([df, df_xlsx], ignore_index=True)              else:                  df_ns = df_ns.append([f], ignore_index=True)          else:              df_ns = df_ns.append([f], ignore_index=True)      else:          df_ns = df_ns.append([f], ignore_index=True)  

https://stackoverflow.com/questions/66020058/empty-list-conditional February 03, 2021 at 09:36AM