如何在树枝中正确循环三维数组？

Question

I have an array setup like so; and I cant seem to loop through the values with twig:

array (size=1)
  'hash' => 
    array (size=7)
      0 => 
        array (size=4)
          'key1' => "val"
          'key2' => "val"
          'key3' => "val"
          'key4' => "val"
      1 => 
        array (size=4)
          'key1' => "val"
          'key2' => "val"
          'key3' => "val"
          'key4' => "val"
      ...

The template code I'm using (in its nth iteration):

  {% for i in hash %}
    {% for j in i %}
      <td>{{ j.key1 }}</td>
      <td>{{ j.key2 }}</td>
      <td>{{ j.key3 }}</td>
      <td>{{ j.key4 }}</td>
    {% endfor %}
  {% endfor %}

I keep getting Array to string conversion errors with the above twig template code.

Answer 1

With the help of vijay4vijju and his reference to dump I was able to loop over the array.

Only a single loop was needed:

{% for key,val in hash %}
  <tr>
    <td>{{ val.key1 }}</td>
    <td>{{ val.key2 }}</td>
    <td>{{ val.key3 }}</td>
    <td>{{ val.key4 }}</td>
  </tr>
{% endfor %}

I would have selected his answer but it technically wasn't the answer, and dump was just a reference to the dump manual.

To enable debugging in twig I used:

$twig = new Twig_Environment($loader, array(
    'debug' => true,
));
$twig->addExtension(new Twig_Extension_Debug());

To troubleshoot this issue I used:

{% for key,val in hash %}
  <pre>{{ dump(val) }}</pre>
  <tr>
    <td>{{ val.key1 }}</td>
    <td>{{ val.key2 }}</td>
    <td>{{ val.key3 }}</td>
    <td>{{ val.key4 }}</td>
  </tr>
{% endfor %}