title: ast.literal_eval() method truncates float value while converting str to dict
body: <p>Here I am trying convert dict to string using <code>ast</code> module. I found that the values are truncated as shown in the output below. how can I get a atual value without truncation here.</p>
  
  <p><strong>code</strong></p>
  
  <pre><code>df = DataFrame({
              'a': np.random.randn(6),
              'b':['foo','bar']*3,
              'c':np.random.randn(6)
              })
  mapping = df.to_dict() 
  d=str(mapping)
  e= ast.literal_eval(d)
  print mapping
  print;print e
  </code></pre>
  
  <p><strong>output</strong></p>
  
  <p><code>{'a': {0: 0.88241526852727104, 1: -0.062779346232699929, 2: -0.058427377402568821, 3: 0.87157579927705897, 4: -1.0399255501591143, 5: 0.11203584043469664}, 'c': {0: 0.56763771194925394, 1: 0.22824054879261255, 2: -0.58324477854217549, 3: -0.2264734421572463, 4: 0.45754374820401839, 5: 1.35849692636584}, 'b': {0: 'foo', 1: 'bar', 2: 'foo', 3: 'bar', 4: 'foo', 5: 'bar'}}</code>
  `</p>
  
  <p><code>{'a': {0: 0.882415268527271, 1: -0.06277934623269993, 2: -0.05842737740256882, 3: 0.871575799277059, 4: -1.0399255501591143, 5: 0.11203584043469664}, 'c': {0: 0.5676377119492539, 1: 0.22824054879261255, 2: -0.5832447785421755, 3: -0.2264734421572463, 4: 0.4575437482040184, 5: 1.35849692636584}, 'b': {0: 'foo', 1: 'bar', 2: 'foo', 3: 'bar', 4: 'foo', 5: 'bar'}}</code></p>