title: Why Unpack function returns array with starting index 1 in PHP
body: <p>Why unpack() function in PHP returns an array of binary data  starting with the array index 1.</p>
  
  <pre><code>$str = "PHP";
  $binary_data = unpack("C*",$str);
  print_r($binary_data);
  </code></pre>
  
  <p>The above PHP scripts prints as below:</p>
  
  <p>Array ( [1] => 80 [2] => 72 [3] => 80 ) </p>