title: Python: Looking to create dictionary with pandas from a csv
body: <p>Here is the dataframe</p>
  <pre><code>          SKU  Green Ball  Brown Ball  Black Ball  Free Gifts  Special Eq
  0  Double Set         1.0         1.0         NaN         1.0         NaN
  1  Green Ball         1.0         NaN         NaN         NaN         NaN
  2  Brown Ball         NaN         1.0         NaN         NaN         NaN
  3  Free Gifts         NaN         NaN         NaN         1.0         NaN
  4  Special Eq         NaN         NaN         NaN         NaN         1.0
  5  Ultima Set         1.0         1.0         NaN         1.0         1.0
  </code></pre>
  <p>The dictionary I want to create</p>
  <pre><code>{
      'Double Set': {'Green Ball': 1.0, 'Brown Ball': 1.0, 'Free Gifts': 1.0},
      'Green Ball': {'Green Ball': 1.0},
      'Brown ball': {'Brown Ball': 1.0},
      'Free Gifts': {'Free Gifts': 1.0},
      'Special Eq': {'Special Eq': 1.0},
      'Ultima Set': {'Green Ball': 1.0, 'Brown Ball': 1.0, 'Free Gifts': 1.0, 'Special Eq': 1.0},
  }
  </code></pre>
  <p>How can I create the above dictionary and also exclude all values looked up to be <code>NaN</code>?</p>