Test if an attribute is present in a tag in BeautifulSoup

I would like to get all the <script> tags in a document and then process each one based on the presence (or absence) of certain attributes.

E.g.,开发者_Python百科 for each <script> tag, if the attribute for is present do something; else if the attribute bar is present do something else.

Here is what I am doing currently:

outputDoc = BeautifulSoup(''.join(output))
scriptTags = outputDoc.findAll('script', attrs = {'for' : True})

But this way I filter all the <script> tags with the for attribute... but I lost the other ones (those without the for attribute).

If i understand well, you just want all the script tags, and then check for some attributes in them?

scriptTags = outputDoc.findAll('script')
for script in scriptTags:
    if script.has_attr('some_attribute'):
        do_something()        

You don't need any lambdas to filter by attribute, you can simply use some_attribute=True in find or find_all.

script_tags = soup.find_all('script', some_attribute=True)

# or

script_tags = soup.find_all('script', {"some-data-attribute": True})

Here are more examples with other approaches as well:

soup = bs4.BeautifulSoup(html)

# Find all with a specific attribute

tags = soup.find_all(src=True)
tags = soup.select("[src]")

# Find all meta with either name or http-equiv attribute.

soup.select("meta[name],meta[http-equiv]")

# find any tags with any name or source attribute.

soup.select("[name], [src]")

# find first/any script with a src attribute.

tag = soup.find('script', src=True)
tag = soup.select_one("script[src]")

# find all tags with a name attribute beginning with foo
# or any src beginning with /path
soup.select("[name^=foo], [src^=/path]")

# find all tags with a name attribute that contains foo
# or any src containing with whatever
soup.select("[name*=foo], [src*=whatever]")

# find all tags with a name attribute that endwith foo
# or any src that ends with  whatever
soup.select("[name$=foo], [src$=whatever]")

You can also use regular expressions with find or find_all:

import re
# starting with
soup.find_all("script", src=re.compile("^whatever"))
# contains
soup.find_all("script", src=re.compile("whatever"))
# ends with 
soup.find_all("script", src=re.compile("whatever$"))

For future reference, has_key has been deprecated is beautifulsoup 4. Now you need to use has_attr

scriptTags = outputDoc.find_all('script')
  for script in scriptTags:
    if script.has_attr('some_attribute'):
      do_something()  

If you only need to get tag(s) with attribute(s), you can use lambda:

soup = bs4.BeautifulSoup(YOUR_CONTENT)

• Tags with attribute

tags = soup.find_all(lambda tag: 'src' in tag.attrs)

OR

tags = soup.find_all(lambda tag: tag.has_attr('src'))

• Specific tag with attribute

tag = soup.find(lambda tag: tag.name == 'script' and 'src' in tag.attrs)

• Etc ...

Thought it might be useful.

you can check if some attribute are present

scriptTags = outputDoc.findAll('script', some_attribute=True)
for script in scriptTags:
    do_something()

By using the pprint module you can examine the contents of an element.

from pprint import pprint

pprint(vars(element))

Using this on a bs4 element will print something similar to this:

{'attrs': {u'class': [u'pie-productname', u'size-3', u'name', u'global-name']},
 'can_be_empty_element': False,
 'contents': [u'\n\t\t\t\tNESNA\n\t'],
 'hidden': False,
 'name': u'span',
 'namespace': None,
 'next_element': u'\n\t\t\t\tNESNA\n\t',
 'next_sibling': u'\n',
 'parent': <h1 class="pie-compoundheader" itemprop="name">\n<span class="pie-description">Bedside table</span>\n<span class="pie-productname size-3 name global-name">\n\t\t\t\tNESNA\n\t</span>\n</h1>,
 'parser_class': <class 'bs4.BeautifulSoup'>,
 'prefix': None,
 'previous_element': u'\n',
 'previous_sibling': u'\n'}

To access an attribute - lets say the class list - use the following:

class_list = element.attrs.get('class', [])

You can filter elements using this approach:

for script in soup.find_all('script'):
    if script.attrs.get('for'):
        # ... Has 'for' attr
    elif "myClass" in script.attrs.get('class', []):
        # ... Has class "myClass"
    else: 
        # ... Do something else

A simple way to select just what you need.

outputDoc.select("script[for]")