title: Combining dataframes to replace missing values
body: <p>I am trying to merge two dataframes together to replace possible missing values. For example:</p>
  <pre><code>df1:
  Fruit     Price
  Apple        5
  Banana       7
  Orange       4
  
  df2: 
  Fruit     Price
  Pear         3
  
  result:
  Fruit     Price
  Apple        5
  Banana       7
  Orange       4
  Pear         3
  </code></pre>
  <p>I've used the concat method to do this and it works, however when both dataframes have the same column instead of having both duplicate values I want to use the data from the first df and ignore the second df. For example:</p>
  <pre><code>df1:    
  Fruit     Price
  Apple        5
  Banana       7
  Orange       4
  Pear         6
  
  df2: 
  Fruit     Price
  Pear         3
  
  result:
  Fruit     Price
  Apple        5
  Banana       7
  Orange       4
  Pear         6
  </code></pre>
  <p>How can I do this so it works on both examples?</p>