title: "ValueError: Unrecognized marker style -d" when looping over markers
body: <p>I'm trying to code <code>pyplot</code> plot that allows different marker styles. The plots are generated in a loop. The markers are picked from a list.
  For demonstration purposes I also included a colour list.
  The versions are <code>Python 2.7.9</code>, <code>IPython 3.0.0</code>, <code>matplotlib 1.4.3.</code></p>
  
  <p>Here's a simple code example:</p>
  
  <pre><code>%matplotlib inline
  import matplotlib.pyplot as plt
  import numpy as np
  
  x=np.arange(0,10)
  y=x**2
  
  markers=['d','-d','-']
  colors=['red', 'green', 'blue']
  
  for i in range(len(markers)):
      plt.plot(x, y, marker=markers[i], color=colors[i])
      plt.show()
  </code></pre>
  
  <p>This manages to produce only the plot for marker='d', for the marker <code>'-d'</code> it returns the error:</p>
  
  <pre><code>...
  C:\Users\batman\AppData\Local\Continuum\Anaconda\lib\site-packages\matplotlib\markers.pyc in set_marker(self, marker)
      245                 self._marker_function = self._set_vertices
      246             except ValueError:
  --&gt; 247                 raise ValueError('Unrecognized marker style {}'.format(marker))
      248 
      249         self._marker = marker
  
  ValueError: Unrecognized marker style -d
  </code></pre>
  
  <p><em>But</em>, I can get it to work by writing <code>plt.plot(x, y, markers[i], color=colors[i])</code> instead.
  The <code>color=...</code> in comparison works.</p>
  
  <p>I assume it has something to do with the the special characters.
  I tried other markers:
  The markers <code>.</code>,<code>*</code> work.
  The markers <code>:</code>,<code>--</code> don't.</p>
  
  <p>I tried prefixing the marker string with <code>r</code> or <code>u</code> (with <code># -*- coding: utf-8 -*-</code>). Didn't help.</p>
  
  <p>Do I have to escape the marker strings or what's wrong here?</p>