title: How to drop null values in Pandas?
body: <p>I try to drop null values of column 'Age' in dataframe, which consists of float values, but it doesn't work.
  I tried</p>
  
  <pre><code>data.dropna(subset=['Age'], how='all')
  data['Age'] = data['Age'].dropna()
  data=data.dropna(axis=1,how='all')
  </code></pre>
  
  <p>It works for other columns but not for 'Age'</p>
  
  <pre><code>    Pclass  Fare    Age Sex
  0   3   7.2500  22.0    1
  1   1   71.2833 38.0    0
  2   3   7.9250  26.0    0
  3   1   53.1000 35.0    0
  4   3   8.0500  35.0    1
  5   3   8.4583  NaN 1
  6   1   51.8625 54.0    1
  7   3   21.0750 2.0 1
  </code></pre>