text: # https://stackoverflow.com/questions/50678599/how-to-merge-two-irregular-data-frames-in-python/50679950#50679950
  import pandas as pd
  import numpy as np 
  
  data_arr1 = [
  	['A', '1-3', 5],
  	['',  '4-7', 23],
  	['',  '8-15', 2],
  	['B', '4-7', 4],
  	['', '8-15', 1],
  	['C', '1-3', 5],
  	['D', '1-3', 2],
  	['E', '1-3', 9]
  ]
  columns1 = ["Car", "Range(Days)", "Sold"];
  
  data_arr2 = [
  	['A', 2],
  	['C', 45],
  	['D', 32],
  	['E', 1]
  ];
  columns2 = ["Car", "Repair_Calls"];
  
  # Creating DataFrames
  df = pd.DataFrame(data_arr1, columns=columns1)
  df2 = pd.DataFrame(data_arr2, columns=columns2)
  
  # Printing Dataframes
  print(df);
  print('\n')
  print(df2);
  
  # Merging df & df2 to get desired output
  df3 = pd.merge(left=df, right=df2, left_on="Car", right_on="Car", how="outer").replace(np.nan, "", regex=True)
  print('\n')
  print(df3)
  
  ### Output &raquo;
  """
  	  Car Range(Days)  Sold
  	0   A         1-3     5
  	1             4-7    23
  	2            8-15     2
  	3   B         4-7     4
  	4            8-15     1
  	5   C         1-3     5
  	6   D         1-3     2
  	7   E         1-3     9
  
  
  	  Car  Repair_Calls
  	0   A             2
  	1   C            45
  	2   D            32
  	3   E             1
  
  
  	  Car Range(Days)  Sold Repair_Calls
  	0   A         1-3     5            2
  	1             4-7    23
  	2            8-15     2
  	3            8-15     1
  	4   B         4-7     4
  	5   C         1-3     5           45
  	6   D         1-3     2           32
  	7   E         1-3     9            1
  """