title: how to keep precision from numpy's array
body: <p>Like Following.</p>
  
  <pre><code>&gt;&gt;&gt;a=numpy.array([-97.173125220360362], dtype=double)
  &gt;&gt;&gt;b=[]
  &gt;&gt;&gt;b.append(a)
  &gt;&gt;&gt;b
  -97.173125220360362
  </code></pre>
  
  <p><strong>But if I assign the value to <code>List</code> directly</strong>. It will lost the last number, like following:</p>
  
  <pre><code>&gt;&gt;&gt;b=[-97.173125220360362] 
  &gt;&gt;&gt;b
  -97.17312522036036
  &gt;&gt;&gt;b=[]
  &gt;&gt;&gt;b.append(-97.173125220360362)
  &gt;&gt;&gt;b
  -97.17312522036036
  </code></pre>
  
  <p>And I found I can't change the last number. like following</p>
  
  <pre><code>&gt;&gt;&gt;b=[-97.173125220360364]     
  &gt;&gt;&gt;b    
  -97.17312522036036    
  &gt;&gt;&gt;numpy.double(b)    
  -97.173125220360362 not -97.173125220360364
  </code></pre>
  
  <p><strong>PS</strong><br>
  I need to save many double numbers from <code>numpy.array</code> into a XML file. I found I lost all of the last numpy by read the XML file.<br>
  <strong>For example</strong>.<br>
  If I save  <code>-97.17312522036036</code> into the XML. and read the value as a string from XML. then convert the string into double value. That will round my vaule</p>