title: too many values to unpack (expected 2) when using for loops
body: <p>I keep on getting the error message : too many values to unpack (expected 2)
  when I tryout the below code :</p>
  <pre><code>
  sheetlist = [df1, df2, df3, df4, df5]
  
  for i, j in sheetlist :
      j = i +1 
      final = i.merge(j, how = &quot;outer&quot;, on = &quot;columnname&quot;)
  
  
  final.head()
  
  </code></pre>
  <p>May anyone know how to solve this?</p>
  <p>Here's the complete Traceback</p>
  <pre><code>ValueError                                Traceback (most recent call last)
  
  &lt;ipython-input-54-981bc6246be4&gt; in &lt;module&gt;()
        3 sheetlist = [df1, df2, df3, df4, df5]
        4 
  ----&gt; 5 for i,j in sheetlist :
        6     j = i + 1
        7     final = i.merge(j, how = &quot;outer&quot;, on = &quot;columnname&quot;)
  
  ValueError: too many values to unpack (expected 2)
  
  </code></pre>