title: List of ascii ordinals to string with python
body: <p>I've got a list of ascii ordinals like:</p>
  
  <pre><code>[102, 114, 97, 110, 99, 101, 115, 99, 111, 0, 0, 0, 0, 0, 0, 0]
  </code></pre>
  
  <p>now I want to transform this to a string removing the null characters at the end.</p>
  
  <p>I've tried with</p>
  
  <pre><code>contenuto_tag = "".join(map(chr, backdata)) 
  </code></pre>
  
  <p>but when I pass it to a function like:</p>
  
  <pre><code>enos.system("php ../trigger_RFID.php %s"%(contenuto_tag))
  </code></pre>
  
  <p>I've got this error:</p>
  
  <pre><code>TypeError: must be string without null bytes, not str
  </code></pre>
  
  <p>maybe because there are the null characters at the end.</p>