在HTML中查找所有标签和属性 [英] Finding all tags and attributes in a HTML
问题描述
我是新手，并且是第一次阅读HTML代码.对于我的研究，我需要知道网页中标签和属性的数量.
I am a newbie and looking at HTML code for first time. For my research I need to know the number of tags and attributes in a webpage.
我查看了各种解析器，发现美丽汤"是最受欢迎的解析器之一.以下代码(取自使用Python解析HTML )显示了解析文件的方法:
I looked at various parser and found Beautiful Soup to be one of the most preferred one. The following code (taken from Parsing HTML using Python) shows the way to parse a file:
import urllib2
from BeautifulSoup import BeautifulSoup
page = urllib2.urlopen('http://www.google.com/')
soup = BeautifulSoup(page)
x = soup.body.find('div', attrs={'class' : 'container'}).text
我发现find_all非常有用，但是需要一个参数来查找某些东西.
I found find_all quite useful, but needs an argument to find something.
有人可以指导我如何了解html页面中的所有标记和属性的数量吗?
Can someone guide me on how to know the count of all tags and attributes in a html page?
Google开发者工具可以在这方面提供帮助吗?
Can google developer tool help in that regard?
推荐答案
如果您致电 find_all() ，不带任何参数，它将以递归方式查找页面上的所有元素.演示:
If you would call find_all() without any arguments, it would find all elements on a page recursively. Demo:
>>> from bs4 import BeautifulSoup
>>>
>>> data = """
... <html><head><title>The Dormouse's story</title></head>
... <body>
... <p class="title"><b>The Dormouse's story</b></p>
...
... <p class="story">Once upon a time there were three little sisters; and their names were
... <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
... <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
... <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
... and they lived at the bottom of a well.</p>
...
... <p class="story">...</p>
... """
>>>
>>> soup = BeautifulSoup(data)
>>> for tag in soup.find_all():
... print tag.name
...
html
head
title
body
p
b
p
a
a
a
p
Padraic向您展示了如何通过BeautifulSoup计算元素和属性.除此之外，下面是使用 lxml.html 的方法:
Padraic showed you how to count elements and attributes via BeautifulSoup. In addition to it, here is how to do the same with lxml.html:
from lxml.html import fromstring
root = fromstring(data)
print int(root.xpath("count(//*)")) + int(root.xpath("count(//@*)"))
作为奖励，我做了一个简单的基准测试，证明后一种方法要快得多(在我的机器上，使用我的设置，并且没有指定解析器，该解析器
As a bonus, I've made a simple benchmark demonstrating that the latter approach is much faster (on my machine, with my setup and without specifying a parser which would make BeautifulSoup use lxml under-the-hood etc..a lot of things can affect the results, but anyway):
$ python -mtimeit -s'import test' 'test.count_bs()'
1000 loops, best of 3: 618 usec per loop
$ python -mtimeit -s'import test' 'test.count_lxml_html()'
10000 loops, best of 3: 114 usec per loop
其中test.py包含:
from bs4 import BeautifulSoup
from lxml.html import fromstring
data = """
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
<p class="story">...</p>
"""
def count_bs():
return sum(len(ele.attrs) + 1 for ele in BeautifulSoup(data).find_all())
def count_lxml_html():
root = fromstring(data)
return int(root.xpath("count(//*)")) + int(root.xpath("count(//@*)"))
这篇关于在HTML中查找所有标签和属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
