title: How do I create the intersection of two hashes?
body: <p>I have two hashes:</p>
  
  <pre><code>hash1 = {1 =&gt; "a" , 2 =&gt; "b" , 3 =&gt; "c" , 4 =&gt; "d"} 
  hash2 = {3 =&gt; "hello", 4 =&gt; "world" , 5 =&gt; "welcome"} 
  </code></pre>
  
  <p>I need a hash which contains common keys in both hashes:</p>
  
  <pre><code>hash3 = {3 =&gt; "hello" , 4 =&gt; "world"}
  </code></pre>
  
  <p>Is it possible to do it without any loop?</p>