title: ImportError: No module named 'numpy.ma'
body: <p>The full error:</p>
  
  <pre><code>import matplotlib
  Traceback (most recent call last):
   File "&lt;pyshell#0&gt;", line 1, in &lt;module&gt;
      import matplotlib
    File "R:\Python34\lib\site-packages\matplotlib\__init__.py", line 180, in &lt;module&gt;
      from matplotlib.cbook import is_string_like
    File "R:\Python34\lib\site-packages\matplotlib\cbook.py", line 34, in &lt;module&gt;
      import numpy.ma as ma
  ImportError: No module named 'numpy.ma'
  </code></pre>
  
  <p>numpy is imported normally.
  How do I install <code>numpy.ma</code>?</p>