title: How to search for a word (exact match) within a string?
body: <p>I am trying to substring search</p>
  
  <pre><code>&gt;&gt;&gt;str1 = 'this'
  &gt;&gt;&gt;str2 = 'researching this'
  &gt;&gt;&gt;str3 = 'researching this '
  
  &gt;&gt;&gt;"[^a-z]"+str1+"[^a-z]" in str2
  False
  
  &gt;&gt;&gt;"[^a-z]"+str1+"[^a-z]" in str3
  False
  </code></pre>
  
  <p>I wanted to True when looking in str3. what am I doing wrong?</p>