title: python - check if nan float in dictionary
body: <pre><code>import numpy as np
  import pandas as pd
  import tia.bbg.datamgr as dm
  mgr = dm.BbgDataManager()
  
  bb_yearb4 = "2016-12-30"
  bb_today = "2017-09-22"
  
  indices = [list of indices]
  sids_index = mgr[indices]
  df_idx = sids_index.get_historical('PX_LAST', bb_yearb4, bb_today)
  
  nan = np.nan
  
  price_test = {}
  for index in indices:
      price_test["{0}".format(index)] = df_idx.loc[bb_today][index]
  </code></pre>
  
  <p>The output shows multiple nan float values:</p>
  
  <pre><code>In [1]: price_test.values()
  Out[1]: [nan, nan, nan, 47913.199999999997, nan, 1210.3299999999999, nan]
  </code></pre>
  
  <p>However, testing for nan shows false:</p>
  
  <pre><code>In [2]: nan in price_test.values()
  Out[2]: False
  </code></pre>
  
  <p>What is the correct way to test this?</p>