Python BeautifulSoup webscraping find_all()：找到完全匹配
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BeautifulSoup webscraping find_all( ): finding exact match
提问by user2436815
I'm using Python and BeautifulSoup for web scraping.
我正在使用 Python 和 BeautifulSoup 进行网页抓取。
Lets say I have the following html code to scrape:
假设我有以下 html 代码要抓取：
<body>
<div class="product">Product 1</div>
<div class="product">Product 2</div>
<div class="product special">Product 3</div>
<div class="product special">Product 4</div>
</body>
Using BeautifulSoup, I want to find ONLY the products with the attribute class="product" (only Product 1 and 2), not the 'special' products
使用 BeautifulSoup，我只想找到属性 class="product"（仅产品 1 和 2）的产品，而不是“特殊”产品
If I do the following:
如果我执行以下操作：
result = soup.find_all('div', {'class': 'product'})
the result includes ALL the products (1,2,3, and 4).
结果包括所有产品（1、2、3 和 4）。
What should I do to find products whose class EXACTLY matches 'product'??
我应该怎么做才能找到类别与“产品”完全匹配的产品？
The Code I ran:
我运行的代码：
from bs4 import BeautifulSoup
import re
text = """
<body>
<div class="product">Product 1</div>
<div class="product">Product 2</div>
<div class="product special">Product 3</div>
<div class="product special">Product 4</div>
</body>"""
soup = BeautifulSoup(text)
result = soup.findAll(attrs={'class': re.compile(r"^product$")})
print result
Output:
输出：
[<div class="product">Product 1</div>, <div class="product">Product 2</div>, <div class="product special">Product 3</div>, <div class="product special">Product 4</div>]
回答by crunch
You can use CSS selectors like so:
你可以像这样使用 CSS 选择器：
result = soup.select('div.product.special')
回答by Martijn Pieters
In BeautifulSoup 4, the classattribute (and several other attributes, such as accesskeyand the headersattribute on table cell elements) is treated as a set; you match against individual elements listed in the attribute. This follows the HTML standard.
在 BeautifulSoup 4 中，class属性（以及其他几个属性，例如accesskey和headers表格单元格元素上的属性）被视为一个集合；您与属性中列出的各个元素进行匹配。这遵循 HTML 标准。
As such, you cannot limit the search to just one class.
因此，您不能将搜索限制为仅一类。
You'll have to use a custom functionhere to match against the class instead:
您必须在此处使用自定义函数来匹配类：
result = soup.find_all(lambda tag: tag.name == 'div' and
tag.get('class') == ['product'])
I used a lambdato create an anonymous function; each tag is matched on name (must be 'div'), and the class attribute must be exactly equal to the list ['product']; e.g. have just the one value.
我用 alambda创建了一个匿名函数；每个标签在名称上匹配（必须是'div'），并且类属性必须完全等于列表['product']；例如只有一个值。
Demo:
演示：
>>> from bs4 import BeautifulSoup
>>> text = """
... <body>
... <div class="product">Product 1</div>
... <div class="product">Product 2</div>
... <div class="product special">Product 3</div>
... <div class="product special">Product 4</div>
... </body>"""
>>> soup = BeautifulSoup(text)
>>> soup.find_all(lambda tag: tag.name == 'div' and tag.get('class') == ['product'])
[<div class="product">Product 1</div>, <div class="product">Product 2</div>]
For completeness sake, here are all such set attributes, from the BeautifulSoup source code:
为了完整起见，以下是来自 BeautifulSoup 源代码的所有此类设置属性：
# The HTML standard defines these attributes as containing a
# space-separated list of values, not a single value. That is,
# class="foo bar" means that the 'class' attribute has two values,
# 'foo' and 'bar', not the single value 'foo bar'. When we
# encounter one of these attributes, we will parse its value into
# a list of values if possible. Upon output, the list will be
# converted back into a string.
cdata_list_attributes = {
"*" : ['class', 'accesskey', 'dropzone'],
"a" : ['rel', 'rev'],
"link" : ['rel', 'rev'],
"td" : ["headers"],
"th" : ["headers"],
"td" : ["headers"],
"form" : ["accept-charset"],
"object" : ["archive"],
# These are HTML5 specific, as are *.accesskey and *.dropzone above.
"area" : ["rel"],
"icon" : ["sizes"],
"iframe" : ["sandbox"],
"output" : ["for"],
}
回答by Tarun Kiran
change your code from
更改您的代码
result = soup.findAll(attrs={'class': re.compile(r"^product$")})
to
到
result = soup.find_all(attrs={'class': 'product'})
and the result is a list and access through index
结果是一个列表和通过索引访问
回答by DeafaltCoder
soup.findAll(attrs={'class': re.compile(r"^product$")})
This code matches anything that doesn't have the productat the end of its class.
此代码匹配product在其类末尾没有 的任何内容。
