Looping through nested arrays

Hello,

I am using Advanced Custom Fields 5, and I have a Repeater field to hold external reviews related to a custom page type. The field is called “external_reviews”, and there are 4 sub fields within it. I would like to iterate over each of the sub-fields, but am struggling to do so using either the array or loop commands.

I am able to use this shortcode:

[array external_reviews debug=true]
[/array]

Which results in this output:

Array
(
    [0] => Array
        (
            [review_url] => http://example.com
            [site_name] => Example Review Site
            [review_snippet] => I love this product!
            [reviewer_name] => John Smith
        )

    [1] => Array
        (
            [review_url] => http://foo.com
            [site_name] => Another Review Site
            [review_snippet] => Hello World!
            [reviewer_name] => Jane Doe
        )

)

However, I am not sure how to then descend into the child arrays to access their values.

In pseudocode, what I am trying to do is:

for each review in external_reviews
  echo site_name
  echo review_url

Thank you.