title: How to filter unwanted words in a text file Haskell
body: <p>I'm trying to write a program in Haskell that can filter out unwanted keywords from a text document. The text document contains information about persons, for example name, age and city, and I want to filter out all of the information associated to those persons who dose not fulfill the keyword.</p>
  
  <p>The database looks something like this: </p>
  
  <pre><code>"Eric" 27 "London"
  "Josefine" 34 "Stockholm"
  "Hans" 50 "London"
  </code></pre>
  
  <p>So if the keyword is "London", I want the following output:</p>
  
  <pre><code>"Eric" 27 "London"
  "Hans" 50 "London"
  </code></pre>
  
  <p>I've tried a bunch of different ways to store the information and to filter out the unwanted persons, but I'm now clueless on how this should be done.</p>