title: Use numpy array to replace pandas DataFrame values
body: <p>I try to use a numpy array to replace the data from a pandas DataFrame (more precisely I want to normalize the data and then set the new columns in the existing DataFrame). It looks like that:</p>
  
  <pre><code># df is a existing pandas dataframe with 10 rows and 3 columns
  new_values = np.random.rand(10,3)
  df = new_values # this is the step I want to solve
  </code></pre>
  
  <p>Of course I want to keep my column and index information of the DataFrame. Someone has any idea how I can make this work?</p>