title: Combining values from two arrays with same keys
body: <p>I have two arrays like this:</p>
  
  <pre><code>$arr1 = Array ( [1] =&gt; ab [2] =&gt; cd [at] =&gt; ef )
  $arr2 = Array ( [1] =&gt; gh [2] =&gt; ij [at] =&gt; kl )
  </code></pre>
  
  <p>I want to combine these two arrays to this array:</p>
  
  <pre><code>$arr3 = Array ( [1] =&gt; ab-gh [2] =&gt; cd-ij [at] =&gt; ef-kl )
  </code></pre>
  
  <p>The keys are the same in the two arrays so I imagine that it is possible to join the values of the arrays with a "-" between like above.</p>
  
  <p>I have googled and tried almost anything (merge, combine, join) but I can't figure it out. Any suggestions?</p>