<p>此元素没有<code>id</code>。它有<code>url</code>,它有字符串<code>id=</code>,但它不是标签的<code>id</code></p>
<p>您应该使用<code>get("href")</code>或regex之类的标准字符串函数来搜索文本中的值。或者可以使用<code>urllib.parse.parse_qs('q=Ascot+...')</code></p>
<pre><code>import urllib.parse
from bs4 import BeautifulSoup
html = '<span class="addr"><a href="p.php?q=Ascot+Vale&amp;sta=vic&amp;id=2758769&amp;address=1%2F39+Sandown+Road%2C+Ascot+Vale" target="_blank">1/39 Sandown Road</a></span>'
soup = BeautifulSoup(html)
href = soup.find('a').get('href')
args = href.split('?')[1]
data = urllib.parse.parse_qs(args)
print(data['id'][0])
</code></pre>
<hr/>
<p><strong>编辑:</strong>使用<code>split()</code>相同</p>
<pre><code>import urllib.parse
from bs4 import BeautifulSoup
html = '<span class="addr"><a href="p.php?q=Ascot+Vale&amp;sta=vic&amp;id=2758769&amp;address=1%2F39+Sandown+Road%2C+Ascot+Vale" target="_blank">1/39 Sandown Road</a></span>'
soup = BeautifulSoup(html)
href = soup.find('a').get('href')
args = href.split('?')[1]
id_ = args.split('id=')[1].split('&')[0]
print(id_)
</code></pre>