title: How to repeat a Pandas DataFrame?
body: <p>This is my DataFrame that should be repeated for 5 times:</p>
  <pre><code>&gt;&gt;&gt; x = pd.DataFrame({'a':1,'b':2}, index = range(1))
  &gt;&gt;&gt; x
     a  b
  0  1  2
  </code></pre>
  <p>I want to have the result like this:</p>
  <pre><code>&gt;&gt;&gt; x.append(x).append(x).append(x)
     a  b
  0  1  2
  0  1  2
  0  1  2
  0  1  2
  </code></pre>
  <p>But there must be a smarter way than appending 4 times. Actually the DataFrame I’m working on should be repeated 50 times.</p>
  <p>I haven't found anything practical, including those like <code>np.repeat</code> ---- it just doesn't work on a DataFrame.</p>
  <p>Could anyone help?</p>