title: Remove word from string start with specific characters
body: <p>I have the following string:</p>
  
  <pre><code>my_string = "This is an example string, ex , excatly , index , hyperextension"
  </code></pre>
  
  <p>I want to remove all words that start with <code>ex</code> in Python.</p>
  
  <p>So the result I want would be:</p>
  
  <pre><code>remove_words_that_start_with_ex("my_string")
  print(my_string)
  </code></pre>
  
  <p>Desired result: </p>
  
  <blockquote>
    <p>This is an string, , , index , hyperextension</p>
  </blockquote>
  
  <p>I tried doing something like this:</p>
  
  <pre><code>main_str = " ".join(filter(lambda x:x[0,1]!='ex', main_str.split()))
  </code></pre>
  
  <p>but it only works with one character, not 2 ("ex").</p>