title: Once I load an excel sheet containing a simple table of data into Python using pd.read_excel, I simply cannot manipulate the data
body: <p>I load the xlsx file using this code:</p>
  
  <pre><code>import pandas as pd
  
  df = pd.read_excel("petr3.xlsx", sheet_name=None)
  </code></pre>
  
  <p>and everything is fine, I can run a <code>print(df)</code> and see that the data is there, but I'm unable to retrieve any data from the table. For instance, if I want to store the column that goes by the name of 'data', I try this:</p>
  
  <pre><code>df["data"]
  </code></pre>
  
  <p>and I get an error:</p>
  
  <blockquote>
    <p>KeyError                                  Traceback (most recent call last)
     in ()
    ----> 1 df["data"]</p>
    
    <p>KeyError: 'data'</p>
  </blockquote>
  
  <p>All the tutorials that I've read, give the same tips and I've tried replicating them but the errors are similar.</p>
  
  <p>(My pandas version is 0.23.0.)</p>