如何用HTML: TreeBuilder找到直接的后代?

Suppose I've a HTML tree like this:

假设我有这样的HTML树:

div
`- ul
   `- li          (*)
   `- li          (*)
   `- li          (*)
   `- li          (*)
      `- ul
         `- li
         `- li
         `- li

How do I select the <li> elements that are marked with (*)? They are direct descendants of the first <ul> element.

如何选择标有(*)的

元素?它们是第一个

元素?它们是第一个元素的直接后代。

Here is how I find the first <ul> element:

如何找到第一个

my $ul = $div->look_down(_tag => 'ul');

Now I've the $ul, but when I do things like:

现在我有了$ul，但当我做以下事情时:

my @li_elements = $ul->look_down(_tag => 'li');

It also finds <li> elements that are buried deeper in the HTML tree.

它还可以找到隐藏在HTML树中更深处的

元素。

How do I find just the <li> elements that are direct descendants of the first <ul> element? I've an unknown number of them. (I can't just select first 4 as in example).

如何找到

元素，它们是第一个

元素,它们是第一个元素的直接后代?我不知道他们的数量。(例如,我不能只选择前4个)。

3 个解决方案

#1

You can get all the children of an HTML::Element object using the content_list method, so all the child nodes of the first <ul> element in the document would be

您可以使用content_list方法来获得HTML的所有子元素:元素对象，因此文档中第一个

use HTML::TreeBuilder;

my $tree = HTML::TreeBuilder->new_from_file('my.html');

my @items = $tree->look_down(_tag => 'ul')->content_list;

But it is far more expressive to use HTML::TreeBuilder::XPath, which lets you find all <li> children of <ul> children of <div> elements anywhere in the document, like this

但是使用HTML::TreeBuilder::XPath更有表现力，它可以让您在文档中任何地方找到

元素

子元素，如下所示
子元素,如下所示

use HTML::TreeBuilder::XPath;

my $tree = HTML::TreeBuilder->new_from_file('my.html');

my @items = $tree->findnodes('//div/ul/li')->get_nodelist;

#2

If you want to use the look_down method you can add an extra criteria to get only the children:

如果您想使用look_down方法，可以添加一个额外的条件，只获取子元素:

my @li_elements = $ul->look_down(_tag => 'li', sub {$_[0]->parent() == $ul});

#3

To make this page perfectly complete, I'll add one more option:

为了使这个页面完美地完成，我将添加一个选项:

@li = grep { $_->tag() eq 'li' } $ul->content_list;

(Where $ul is your top-level element)

(其中$ul是您的*元素)

#1