title: Moving desired row to the top of pandas Data Frame
body: <p>In <code>pandas</code>, how can I copy or move a row to the top of the Data Frame without creating a copy of the Data Frame?</p>
  
  <p>For example, I managed to do almost what I want with the code below, but I have the impression that there might be a better way to accomplish this:</p>
  
  <pre><code>import pandas as pd
  
  df = pd.DataFrame({'Probe':['Test1','Test2','Test3'], 'Sequence':['AATGCGT','TGCGTAA','ATGCATG']})
  
  df
  
     Probe Sequence
  0  Test1  AATGCGT
  1  Test2  TGCGTAA
  2  Test3  ATGCATG
  
  df_shifted = df.shift(1)
  
  df_shifted
  
     Probe Sequence
  0    NaN      NaN
  1  Test1  AATGCGT
  2  Test2  TGCGTAA
  
  
  df_shifted.ix[0] = df.ix[2]
  
  df_shifted
  
     Probe Sequence
  0  Test3  ATGCATG
  1  Test1  AATGCGT
  2  Test2  TGCGTAA
  </code></pre>