title: Select data from pandas multiindex pivottable
body: <p>I have a multiindex dataframe (pivottable) with 1703 rows that looks like this: </p>
  
  <pre><code>Local code     Ex Code    ...  Value      
  159605         FR1xx      ...  30               
  159973         FR1xx      ...  50    
  ...
  ZZC923HDV906   XYxx       ...  20
  </code></pre>
  
  <p>There are either numerical local codes (e.g. 159973) or local codes consisting of both characters and strings (e.g. ZZC923HDV906)
  I'd like to select the data by the first index column (Local code). This works well for the string characters with the following code</p>
  
  <pre><code>pv_comb[(pv_comb.index.get_level_values("Local code") == "ZZC923HDV906")] 
  </code></pre>
  
  <p>However I don't manage to select the numerical values:</p>
  
  <pre><code>pv_comb[(pv_comb.index.get_level_values("Local code") == 159973)]
  </code></pre>
  
  <p>This returns an empty dataframe. 
  Is it possible to convert the values in the first column of the multiindex into string characters and then select the data? </p>