读BeautifulSoup官方文档之html树的搜索(2)

除了find()和find_all(), 这里还提供了许多类似的方法我就细讲了, 参数和用法都差不多, 最后四个是next, previous是以.next/previous_element()来说的...

Signature: find_parents(name, attrs, string, limit, **kwargs)

Signature: find_parent(name, attrs, string, **kwargs)

Signature: find_next_siblings(name, attrs, string, limit, **kwargs)

Signature: find_next_sibling(name, attrs, string, **kwargs)

Signature: find_previous_siblings(name, attrs, string, limit, **kwargs)

Signature: find_previous_sibling(name, attrs, string, **kwargs)

Signature: find_all_next(name, attrs, string, limit, **kwargs)

Signature: find_next(name, attrs, string, **kwargs)

Signature: find_all_previous(name, attrs, string, limit, **kwargs)

Signature: find_previous(name, attrs, string, **kwargs)

BeautifulSoup也提供CSS选择器, 用法大致与css选择器相同, 我css也只是入门级别, 这里就不多解释了... :

 soup.select("title")
 # [<title>The Dormouse's story</title>]

 soup.select("p nth-of-type(3)")
 # [<p class="story">...</p>]

 soup.select("body a")
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,
 #  <a class="sister" href="http://example.com/lacie"  id="link2">Lacie</a>,
 #  <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

 soup.select("html head title")
 # [<title>The Dormouse's story</title>]

 soup.select("head > title")
 # [<title>The Dormouse's story</title>]

 soup.select("p > a")
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,
 #  <a class="sister" href="http://example.com/lacie"  id="link2">Lacie</a>,
 #  <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

 soup.select("p > a:nth-of-type(2)")
 # [<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>]

 soup.select("p > #link1")
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>]

 soup.select("body > a")
 # []

 #上面好像看懂了, 应该是 > 的话就是必须是孩子, 空格的话表示子孙.

 soup.select("#link1 ~ .sister")
 # [<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,
 #  <a class="sister" href="http://example.com/tillie"  id="link3">Tillie</a>]

 soup.select("#link1 + .sister")
 # [<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>]

 soup.select(".sister")
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,
 #  <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,
 #  <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

 soup.select("#link1")
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>]

 soup.select("a#link2")
 # [<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>]

 #下面好像是通过id寻找 :
 soup.select("#link1")
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>]

 soup.select("a#link2")
 # [<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>]

 #匹配任意一个
 soup.select(“#link1,#link2”)
 # [<a class=”sister” href=”http://example.com/elsie” id=”link1”>Elsie</a>,
 # <a class=”sister” href=”http://example.com/lacie” id=”link2”>Lacie</a>]

 #当然可以用属性的值来匹配
 soup.select('a[href="http://example.com/elsie"]')
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>]

 soup.select('a[href^="http://example.com/"]')
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,
 #  <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,
 #  <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

 soup.select('a[href$="tillie"]')
 # [<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

 soup.select('a[href*=".com/el"]')
 # [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>]

 #这个真看不懂
 multilingual_markup = """
  <p lang="en">Hello</p>
  <p lang="en-us">Howdy, y'all</p>
  <p lang="en-gb">Pip-pip, old fruit</p>
  <p lang="fr">Bonjour mes amis</p>
 """
 multilingual_soup = BeautifulSoup(multilingual_markup)
 multilingual_soup.select('p[lang|=en]')
 # [<p lang="en">Hello</p>,
 #  <p lang="en-us">Howdy, y'all</p>,
 #  <p lang="en-gb">Pip-pip, old fruit</p>]

 #选一个可以用select_one()
 soup.select_one(".sister")
 # <a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>