我需要找到所有< div>的id属性的值.具有< span>的元素儿童.
例如,给定这个HTML
<div id="a1"> <span> xa1 </span> </div> <div id="a2"> <p>...</p> <span> xa2 </span> </div> <div id="a3"> <p> <span> xa3 </span> </p> </div> <div id="a4"> <p>...</p> </div> <div id="b1"> </div> <span> xb1 </span> <div id="b2"> </div> <p> <span> xb1 </span> </p> <div id="b3"> </div> <p>.</p> <span> xb3 </span>
我需要得到：a1,仅此而已.
因为CSS选择器没有类似正向前瞻的东西,所以我需要逐步搜索HTML,但我不知道如何.
如何修改下一个源,只获得a1？
use 5.014;
use warnings;
use Mojo::DOM;
my $html = do {local $/; <DATA>};
my $dom = Mojo::DOM->new($html);
for my $div ($dom->find('div')->each) {
#say "DIV[[$div]]";
my @spans = $div->find('div > span')->each; #found a1 and a2 ;(
say $div->attr('id') if (@spans == 1);
}
__DATA__
<div id="a1"> <span> xa1 </span> </div>
<div id="a2"> <p>...</p> <span> xa2 </span> </div>
<div id="a3"> <p> <span> xa3 </span> </p> </div>
<div id="a4"> <p>...</p> </div>
<div id="b1"> </div> <span> xb1 </span>
<div id="b2"> </div> <p> <span> xb1 </span> </p>
<div id="b3"> </div> <p>.</p> <span> xb3 </span>
<p id="p1"> <span> xp1 </span> </p>
<p id="p2"> <p>...</p> <span> xp2 </span> </p>
<p id="p3"> <p> <span> xp3 </span> </p> </p>
<p id="p4"> <p>...</p> </p>
解决方法
您可以使用css样式选择器和Mojo :: DOM的
parent方法以稍微迂回的方式获取您正在寻找的元素：
use strict;
use warnings;
use feature ":5.10";
use Mojo::DOM;
my $html = do{ local $/; <DATA>};
my $dom = Mojo::DOM->new($html);
# searches for div elements with spans as the first child
for my $div ( $dom->find('div > span:first-child')->parent->each ) {
say "id: " . $div->attr('id') if $div->attr('id');
}
__DATA__
<div id="a1"> <span> xa1 </span> </div>
<div id="a2"> <p>...</p> <span> xa2 </span> </div>
<div id="a3"> <p> <span> xa3 </span> </p> </div>
<div id="a4"> <p>...</p> </div>
<div id="b1"> </div> <span> xb1 </span>
<div id="b2"> </div> <p> <span> xb1 </span> </p>
<div id="b3"> </div> <p>.</p> <span> xb3 </span>
<p id="p1"> <span> xp1 </span> </p>
<p id="p2"> <p>...</p> <span> xp2 </span> </p>
<p id="p3"> <p> <span> xp3 </span> </p> </p>
<p id="p4"> <p>...</p> </p>
输出：
id: a1
或者,如果您知道它只是您想要的第一个这样的div,那么以下内容将起作用：
say "id: " . $dom->at('div > span:first-child')->parent->attr('id');