Twig中的输出数组

Question

I created the array in Twig and tried to output its values:

 {% set comments = [
    {'author': 'Bhaumik Patel', 'comment_body': 'Test comment body', 'date': '2 Aug 2013'},
    {'author': 'Bhaumik Patel', 'comment_body': 'Test comment body', 'date': '2 Aug 2013'},
    {'author': 'Bhaumik Patel', 'comment_body': 'Test comment body', 'date': '2 Aug 2013' },
] %}

Loop to iterate:

{% for key,item in comments %}
    {% for comment in item %}
       {{ attribute(comment, key).author }}
    {% endfor %}
{% endfor %}

But I get a white screen. What I am doing wrong?

I tried to do it as described in Accessing array values using array key from Twig.