title: Pandas: Fill in missing indexes with specific ordered values that are already in column.
body: <p>I have extracted a one-column dataframe with specific values. Now this is what the dataframe looks like:</p>
  
  <pre><code>           Commodity  
  0              Cocoa
  4             Coffee
  6              Maize
  7               Rice
  10             Sugar
  12             Wheat
  </code></pre>
  
  <p>Now I want to respectively fill each index that has no value with the value above it in the column so It should look something like this:</p>
  
  <pre><code>            Commodity  
  0               Cocoa
  1               Cocoa
  2               Cocoa
  3               Cocoa
  4              Coffee
  5              Coffee
  6               Maize
  7                Rice
  8                Rice
  9                Rice
  10              Sugar
  11              Sugar
  12              Wheat
  </code></pre>
  
  <p>I don't seem to get anything from the pandas documentation Working with Text Data. Thanks for your help! </p>