beautifulsoupvsxmltodict
beautifulsoup is a Python library for pulling data out of HTML and XML files. It creates parse trees from the source code that can be used to extract data from HTML, which is useful for web scraping. With beautifulsoup, you can search, navigate, and modify the parse tree. It sits atop popular Python parsers like lxml and html5lib, allowing users to try out different parsing strategies or trade speed for flexibility.
beautifulsoup has a number of useful methods and attributes that can be used to extract and manipulate data from an HTML or XML document. Some of the key features include:
- Searching the parse tree
You can search the parse tree using the various search methods that beautifulsoup provides, such as find(), find_all(), and select(). These methods take various arguments to search for specific tags, attributes, and text, and return a list of matching elements. - Navigating the parse tree
You can navigate the parse tree using the various navigation methods that beautifulsoup provides, such as next_sibling, previous_sibling, next_element, previous_element, parent, and children. These methods allow you to move up, down, and around the parse tree. - Modifying the parse tree
You can modify the parse tree using the various modification methods that beautifulsoup provides, such as append(), extend(), insert(), insert_before(), and insert_after(). These methods allow you to add new elements to the parse tree, or to change the position of existing elements. - Accessing tag attributes
You can access the attributes of a tag using the attrs property. This property returns a dictionary of the tag's attributes and their values. - Accessing tag text
You can access the text within a tag using the string property. This property returns the text as a string, with any leading or trailing whitespace removed.
With the above feature one can easily extract data out of HTML or XML files. It is widely used in web scraping and other data extraction projects.
It also has features for parsing XML files, special methods for dealing with HTML forms, pretty printing HTML and a few other functionalities.
xmltodict is a Python library that allows you to work with XML data as if it were JSON. It allows you to parse XML documents and convert them to dictionaries, which can then be easily manipulated using standard dictionary operations.
You can also use the library to convert a dictionary back into an XML document. xmltodict is built on top of the popular lxml library and provides a simple, intuitive API for working with XML data.
Note that despite using lxml conversion speeds can be quite slow for large XML documents and in web scraping this should be used to parse specific snippets instead of whole HTML documents.
xmltodict pairs well with JSON parsing tools like jmespath or jsonpath. Alternatively, it can be used in reverse mode to parse JSON documents using HTML parsing tools like CSS selectors and XPath.
It can be installed via pip by running pip install xmltodict command.
Highlights
Example Use
from bs4 import BeautifulSoup
# this is our HTML page:
html = """
<head>
<title>Hello World!</title>
</head>
<body>
<div id="product">
<h1>Product Title</h1>
<p>paragraph 1</p>
<p>paragraph2</p>
<span class="price">$10</span>
</div>
</body>
"""
soup = BeautifulSoup(html)
# we can iterate using dot notation:
soup.head.title
"Hello World"
# or use find method to recursively find matching elements:
soup.find(class_="price").text
"$10"
# the selected elements can be modified in place:
soup.find(class_="price").string = "$20"
# beautifulsoup also supports CSS selectors:
soup.select_one("#product .price").text
"$20"
# bs4 also contains various utility functions like HTML formatting
print(soup.prettify())
"""
<html>
<head>
<title>
Hello World!
</title>
</head>
<body>
<div id="product">
<h1>
Product Title
</h1>
<p>
paragraph 1
</p>
<p>
paragraph2
</p>
<span class="price">
$20
</span>
</div>
</body>
</html>
"""
import xmltodict
xml_string = """
<book>
<title>The Great Gatsby</title>
<author>F. Scott Fitzgerald</author>
<publisher>Charles Scribner's Sons</publisher>
<publication_date>1925</publication_date>
</book>
"""
book_dict = xmltodict.parse(xml_string)
print(book_dict)
{'book': {'title': 'The Great Gatsby',
'author': 'F. Scott Fitzgerald',
'publisher': "Charles Scribner's Sons",
'publication_date': '1925'}}
# and to reverse:
book_xml = xmltodict.unparse(book_dict)
print(book_xml)
# the xml can be loaded and parsed using parsel or beautifulsoup:
from parsel import Selector
sel = Selector(book_xml)
print(sel.css('publication_date::text').get())
'1925'