title: How to join array values in PHP
body: <p>I have a PHP array:</p>
  
  <pre><code>array
    0 =&gt; 
      array
        'cid' =&gt; string '18427' (length=5)
    1 =&gt; 
      array
        'cid' =&gt; string '17004' (length=5)
    2 =&gt; 
      array
        'cid' =&gt; string '19331' (length=5)
  </code></pre>
  
  <p>I want to join the values so I can get a string like this:</p>
  
  <pre><code>18427,17004,19331
  </code></pre>
  
  <p>I tried the <code>implode</code> PHP function, But I get an error:</p>
  
  <pre><code>A PHP Error was encountered
  </code></pre>
  
  <p>How can join only the values which are in <code>cid</code>?</p>