title: Boolean Indexing with multiple conditions
body: <p>I have a <strong>Pandas DF</strong> where I need to <strong>filter</strong> out some rows that contains values == 0 for feature 'a' and feature 'b'.</p>
  
  <p>In order to inspect the values, I run the following:</p>
  
  <pre><code>DF1 = DF[DF['a'] == 0]
  </code></pre>
  
  <p>Which returns the right values. Similarly, by doing this:</p>
  
  <pre><code>DF2 = DF[DF['b'] == 0]
  </code></pre>
  
  <p>I can see the 0 values for feature 'b'.</p>
  
  <p>However, if I try to combine these 2 in a single line of code using the OR operand:</p>
  
  <pre><code>DF3 = DF[DF['a'] == 0 |  DF['b'] == 0]
  </code></pre>
  
  <p>I get this:</p>
  
  <pre><code>TypeError: cannot compare a dtyped [float64] array with a scalar of type [bool]
  </code></pre>
  
  <p>What's happening here?</p>