Question

我想从this book中提取一首随机诗。

使用BeautifulSoup，我能够找到标题和散文。

print soup.find('div', class_="pre_poem").text
print soup.find('table', class_="poem").text

但我想找到所有的诗并挑选一首。我应该使用正则表达式并匹配所有之间 <h3>和</span></p>？

Answer 1

假设您已经有一个合适的soup对象可供使用，以下内容可能会帮助您入门：

poem_ids = []

for section in soup.find_all('ol', class_="TOC"):
    poem_ids.extend(li.find('a').get('href') for li in section.find_all('li'))

poem_ids = [id[1:] for id in poem_ids[:-1] if id]
poem_id = random.choice(poem_ids)

poem_start = soup.find('a', id=poem_id)
poem = poem_start.find_next()
poem_text = []

while True:
    poem = poem.next_element

    if poem.name == 'h3':
        break

    if poem.name == None:
        poem_text.append(poem.string)

print '\n'.join(poem_text).replace('\n\n\n', '\n')

首先从页面顶部的目录中提取诗歌列表。这些包含每首诗的唯一ID。接下来，选择随机ID，然后根据该ID提取匹配的诗。

例如，如果选择了第一首诗，您将看到以下输出：

"The Arrow and the Song," by Longfellow (1807-82), is placed first in
this volume out of respect to a little girl of six years who used to
love to recite it to me. She knew many poems, but this was her
favourite.


I shot an arrow into the air,
It fell to earth, I knew not where;
For, so swiftly it flew, the sight
Could not follow it in its flight.


I breathed a song into the air,
It fell to earth, I knew not where;
For who has sight so keen and strong
That it can follow the flight of song?


Long, long afterward, in an oak
I found the arrow, still unbroke;
And the song, from beginning to end,
I found again in the heart of a friend.


Henry W. Longfellow.

这是通过使用BeautifulSoup从每个元素中提取所有文本，直到找到下一个<h3>标记，然后删除任何额外的换行符来完成的。

Answer 2

请改用html document parser。就意外的后果而言，它更安全。

所有程序员不鼓励用正则表达式解析HTML的原因是页面的HTML标记不是静态的，特别是如果你的源HTML是一个网页。正则表达式更适合字符串。

使用正则表达式需要您自担风险。

如何在标签之间提取所有文字？

2 个答案: