title: How to write most efficient way to add a value for an column in dataframe python?
body: <p>I have one data frame <code>df</code> consisting of a  2 columns(word and meaning/definition of that word). I want to use the <code>Collections.Counter</code> object for each definition of a word and count the frequency of words occurring in the definition in the most pythonic way possible. </p>
  
  <p>The traditional approach would be to iterate over the data frame using the <code>iterrows()</code> methods and do the computations.</p>
  
  <p>Sample output</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;table style="height: 59px;" border="True" width="340"&gt;
    &lt;tbody&gt;
      &lt;tr&gt;
        &lt;td&gt;Word&lt;/td&gt;
        &lt;td&gt;Meaning&lt;/td&gt;
        &lt;td&gt;Word Freq&lt;/td&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
        &lt;td&gt;Array&lt;/td&gt;
        &lt;td&gt;collection of homogeneous datatype&lt;/td&gt;
        &lt;td&gt;{'collection':1,'of':1....}&lt;/td&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
        &lt;td&gt;&amp;nbsp;&lt;/td&gt;
        &lt;td&gt;&amp;nbsp;&lt;/td&gt;
        &lt;td&gt;&amp;nbsp;&lt;/td&gt;
      &lt;/tr&gt;
    &lt;/tbody&gt;
  &lt;/table&gt;</code></pre>
  </div>
  </div>
  </p>