title: Merging two data frames based on the index column
body: <p>I have two dataframes, I wanted to merge them into one single dataframe based on the matching row. My dataframe looks like this </p>
  
  <p>DF_1</p>
  
  <pre>
  Set_1   Fax_1   Fax_2
  Abc_1   45  76
  Abc_2   46  77
  Abc_3   47  78
  Abc_4   48  79
  Abc_5   49  80
  Abc_6   50  81
  Abc_7   51  82
  Abc_8   52  83
  Abc_9   53  84
  Abc_10  54  85
  </pre>
  
  <p>df_2</p>
  
  <pre>
  Set_1   Fax_3   Fax_4
  Abc_1   69  42
  Abc_2   70  43
  Abc_3   71  44
  Abc_6   72  45
  Abc_5   73  46
  Abc_6   74  47
  Abc_7   75  48
  Abc_8   76  49
  Abc_9   77  50
  Abc_10  78  51
  Abc_11  55  86
  Abc_12  56  87
  Abc_13  57  88
  Abc_14  58  89
  Abc_15  59  90
  Abc_16  60  91
  </pre>
  
  <p>The second one is a bigger dataframe and what I need as in my output file, as,</p>
  
  <pre>
  Set_1   Fax_1   Fax_2   Fax_3   Fax_4
  Abc_1   45  76  69  42
  Abc_2   46  77  70  43
  Abc_3   47  78  71  44
  Abc_4   48  79  72  45
  Abc_5   49  80  73  46
  Abc_6   50  81  74  47
  Abc_7   51  82  75  48
  Abc_8   52  83  76  49
  Abc_9   53  84  77  50
  Abc_10  54  85  78  51
  </pre>
  
  <p>This is what I tried with merge,</p>
  
  <pre><code>merged =df.merge(df_annon, on='Set_1')
  merged.head()
  </code></pre>
  
  <p>But it is just giving me the header as output.
  Any help or guidance is much appreciated..!!</p>