title: How can I convert a string to array?
body: <p>I have a string like this:</p>
  
  <pre><code>$str = '[{"file_id":"AgADBAADX6oxGyqs0FJLW3rZ3g6_fDnO-RkABB0pg6HTwdv7EqUBAAEC","file_size":1347,"file_path":"photos\/file_2.jpg","width":90,"height":75},{"file_id":"AgADBAADX6oxGyqs0FJLW3rZ3g6_fDnO-RkABIMbRhad2WVdE6UBAAEC","file_size":17588,"width":320,"height":265},{"file_id":"AgADBAADX6oxGyqs0FJLW3rZ3g6_fDnO-RkABHSo-WKlRRfBEaUBAAEC","file_size":18480,"width":330,"height":273}]';
  </code></pre>
  
  <p>How can I access items in it?</p>
  
  <hr>
  
  <p>I can use regex to select them, something like <code>/"file_id":"(.*?)"/</code>. But that's not clean at all. Is there any approach to make a array (or an object) of string above? </p>