title: Return dataframe subset based on a list of boolean values
body: <p>I'm trying to slice a dataframe based on list of values, how would I go about this?</p>
  
  <p>Say I have an expression or a list <code>l = [0,1,0,0,1,1,0,0,0,1]</code></p>
  
  <p>How to return those rows in a dataframe, <code>df</code>, when the corresponding value in the expression/list is 1? In this example, I would include rows where index is 1, 4, 5, and 9.</p>