title: Pandas: Sorting rows based on a value of a column
body: <p>I have a dataframe <code>df</code> like this :   </p>
  
  <pre><code>ID    NAME    AGE
  -----------------
  M43   ab      32
  M32   df      12
  M54   gh      34
  M43   ab      98
  M43   ab      36
  M43   cd      32
  M32   cd      39
  M43   ab      67
  </code></pre>
  
  <p>I need to sort the rows based on the <code>ID</code> column.<br>
  The output <code>df_grouped</code> should look like :</p>
  
  <pre><code>ID    NAME    AGE
  -----------------
  M43   ab      32
  M43   ab      98
  M43   ab      36
  M43   cd      32
  M43   ab      67
  M32   df      12
  M32   cd      39
  M54   gh      34
  </code></pre>
  
  <p>I tried something like :</p>
  
  <pre><code>df_grouped = df.group_by(df.ID)
  
  for id in list(df.ID.unique()):
     grouped_df_list.append(df_grouped.get_group(id))
  </code></pre>
  
  <p>Is there any better way to do this ?</p>