title: Check if string is in pandas Dataframe column, and create new Dataframe
body: <p>I am trying to check if a string is in a Pandas column. I tried doing it two ways but they both seem to check for a substring.</p>
  
  <pre><code>itemName = "eco drum ecommerce"
  words = self.itemName.split(" ")
  df.columns = ['key','word','umbrella', 'freq']
  df = df.dropna()
  df = df.loc[df['word'].isin(words)]
  </code></pre>
  
  <p>I also tried this way, but this also checks for substring</p>
  
  <pre><code>words = self.itemName.split(" ")
  words = '|'.join(words)
  df.columns = ['key','word','umbrella', 'freq']
  df = df.dropna()
  df = df.loc[df['word'].str.contains(words, case=False)]
  </code></pre>
  
  <p>The word was this: <code>"eco drum"</code>.</p>
  
  <p>Then I did this:</p>
  
  <pre><code>words = self.itemName.split(" ")
  words = '|'.join(words)
  </code></pre>
  
  <p>To end up with this:</p>
  
  <pre><code>eco|drum
  </code></pre>
  
  <p>This is the <code>"word"</code> column:</p>
  
  <p><a href="https://i.stack.imgur.com/ptubm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ptubm.png" alt="enter image description here"></a></p>
  
  <p>Thank you, is it possible this way to not match substrings?</p>