title: What is the difference between "include?" and "match"?
body: <p>This is my code:</p>
  
  <pre><code>fred = {
      'age' =&gt; 63,
      'gender' =&gt; 'male',
      'favorite painters' =&gt; ['Monet', 'Constable', 'Da Vinci']
  }
  
  
  
  fred.delete_if { |k,v| k.match(/[a]/) }
  puts fred
  </code></pre>
  
  <p>The result shows <code>{"gender"=&gt;"male"}</code>.</p>
  
  <p>If I change the code to</p>
  
  <pre><code>fred.delete_if { |k,v| k.include?(/[a]/) }
  </code></pre>
  
  <p>it won't work.</p>
  
  <p>Can anyone explain why to me?</p>