title: Python3 ImportError: No module named '_tkinter' on Ubuntu
body: <p>The current version of Python3 is 3.5.2 when I import matplotlib it retuned the following error</p>
  
  <pre><code>&gt;&gt;&gt; import matplotlib.pyplot as plt
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/local/lib/python3.5/site-packages/matplotlib/pyplot.py", line 115, in &lt;module&gt;
      _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
    File "/usr/local/lib/python3.5/site-packages/matplotlib/backends/__init__.py", line 32, in pylab_setup
      globals(),locals(),[backend_name],0)
    File "/usr/local/lib/python3.5/site-packages/matplotlib/backends/backend_tkagg.py", line 6, in &lt;module&gt;
      from six.moves import tkinter as Tk
    File "/usr/local/lib/python3.5/site-packages/six.py", line 92, in __get__
      result = self._resolve()
    File "/usr/local/lib/python3.5/site-packages/six.py", line 115, in _resolve
      return _import_module(self.mod)
    File "/usr/local/lib/python3.5/site-packages/six.py", line 82, in _import_module
      __import__(name)
    File "/usr/local/lib/python3.5/tkinter/__init__.py", line 35, in &lt;module&gt;
      import _tkinter # If this fails your Python may not be configured for Tk
  ImportError: No module named '_tkinter'
  </code></pre>
  
  <p>And import tkinter</p>
  
  <pre><code>Python 3.5.2 (default, Jan 19 2017, 11:29:22)
  [GCC 4.8.4] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import tkinter
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/local/lib/python3.5/tkinter/__init__.py", line 35, in &lt;module&gt;
      import _tkinter # If this fails your Python may not be configured for Tk
  ImportError: No module named '_tkinter'
  &gt;&gt;&gt;
  </code></pre>
  
  <p>It seems that tkinter has already been intalled.</p>
  
  <p>I have installed tk and tcl by </p>
  
  <pre><code>sudo apt-get install tk-dev
  sudo apt-get install tk8.6-dev
  </code></pre>
  
  <p>And OS is Ubuntu 14.04.</p>
  
  <p>I think it is the reason that TK was not configured on Python3, but I'm not sure.  Many people said I should rebuild and reinstall Python3 with tk, however I don't think it is an elegant way to solve this problem.</p>
  
  <p>How can I fix this problem?</p>