Navigation using Beautiful Soup

Navigation in Beautiful Soup is almost the same as the searching methods. In navigating, instead of methods, there are certain attributes that facilitate the navigation. As we already saw in Chapter 2, Creating a BeautifulSoup Object, Beautiful Soup uses a different TreeBuilder to build the HTML/XML tree. So each Tag or NavigableString object will be a member of the resulting tree with the Beautiful Soup object placed at the top and other objects as the nodes of the tree.

The following code snippet is an example for an HTML tree:

html_markup = """<div class="ecopyramid">
  <ul id="producers">
    <li class="producerlist">
      <div class="name">plants</div>
      <div class="number">100000</div>
    </li>
    <li class="producerlist">
      <div class="name">algae</div>
      <div class="number&quot...