python pandas: filter out records with null or empty string for a given field
<p>I am trying to filter out records whose field_A is null or empty string in the data frame like below:</p>

<pre><code>my_df[my_df.editions is not None]
my_df.shape
</code></pre>

<p>This gives me error:</p>

<pre><code>---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
&lt;ipython-input-40-e1969e0af259&gt; in &lt;module&gt;()
      1 my_df['editions'] = my['editions'].astype(str)
----&gt; 2 my_df = my_df[my_df.editions is not None]
      3 my_df.shape

/home/edamame/anaconda2/lib/python2.7/site-packages/pandas/core/frame.pyc in __getitem__(self, key)
   1995             return self._getitem_multilevel(key)
   1996         else:
-&gt; 1997             return self._getitem_column(key)
   1998 
   1999     def _getitem_column(self, key):

/home/edamame/anaconda2/lib/python2.7/site-packages/pandas/core/frame.pyc in _getitem_column(self, key)
   2002         # get column
   2003         if self.columns.is_unique:
-&gt; 2004             return self._get_item_cache(key)
   2005 
   2006         # duplicate columns &amp; possible reduce dimensionality

/home/edamame/anaconda2/lib/python2.7/site-packages/pandas/core/generic.pyc in _get_item_cache(self, item)
   1348         res = cache.get(item)
   1349         if res is None:
-&gt; 1350             values = self._data.get(item)
   1351             res = self._box_item_values(item, values)
   1352             cache[item] = res

/home/edamame/anaconda2/lib/python2.7/site-packages/pandas/core/internals.pyc in get(self, item, fastpath)
   3288 
   3289             if not isnull(item):
-&gt; 3290                 loc = self.items.get_loc(item)
   3291             else:
   3292                 indexer = np.arange(len(self.items))[isnull(self.items)]

/home/edamame/anaconda2/lib/python2.7/site-packages/pandas/indexes/base.pyc in get_loc(self, key, method, tolerance)
   1945                 return self._engine.get_loc(key)
   1946             except KeyError:
-&gt; 1947                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   1948 
   1949         indexer = self.get_indexer([key], method=method, tolerance=tolerance)

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4154)()

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4018)()

pandas/hashtable.pyx in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12368)()

pandas/hashtable.pyx in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12322)()

KeyError: True
</code></pre>

<p>or</p>

<pre><code>my_df[my_df.editions != None]
my_df.shape
</code></pre>

<p>This one gave no error but didn't filter out any None values. </p>

<p>I also tried:</p>

<pre><code>my_df = my_df[my_df.editions.notnull()]
</code></pre>

<p>This one doesn't give error but doesn't filter out any None values either.</p>

<p>Could anyone please advise how to solve this problem? Thanks!</p>