title: Filling out empty cells with lists of values
body: <p>I have a data frame that looks like below:</p>
  
  <pre><code>         City         State              Country
        Chicago            IL        United States
         Boston                    
      San Diego            CA        United States
    Los Angeles            CA        United States
  San Francisco
     Sacramento     
      Vancouver            BC               Canada
        Toronto  
  </code></pre>
  
  <p>And I have 3 lists of values that are ready to fill in the None cells:</p>
  
  <pre><code>city = ['Boston', 'San Francisco', 'Sacramento', 'Toronto']
  state = ['MA', 'CA', 'CA', 'ON']
  country = ['United States', 'United States', 'United States', 'Canada']
  </code></pre>
  
  <p>The order of the elements in these list are correspondent to each other. Thus, the first items across all 3 lists match each other, and so forth. How can I fill out the empty cells and produce a result like below?</p>
  
  <pre><code>         City         State              Country
        Chicago            IL        United States
         Boston            MA        United States
      San Diego            CA        United States
    Los Angeles            CA        United States
  San Francisco            CA        United States
     Sacramento            CA        United States
      Vancouver            BC               Canada
        Toronto            ON               Canada
  </code></pre>
  
  <p>My code gives me an error and I'm stuck.</p>
  
  <pre><code>if df.loc[df['City'] == 'Boston']:
      'State' = 'MA'
  </code></pre>
  
  <p>Any solution is welcome. Thank you.</p>