Use findall() to find all matching elements in XML. 1. Get all book elements through root.findall('book') and iterate; 2. Use book.find('title').text to extract child element text; 3. Use book.get('id') to obtain attribute values; 4. Support simple XPaths such as 'book[@id]' or './/title' to find attributes or deep nested elements; 5. Conditional filtering needs to be implemented manually (such as price > 40). This method returns a list of matching elements, combining find() and findtext() can efficiently extract structured data.

Using the xml.etree.ElementTree module to parse XML in Python is a common requirement. findall() method is used to find all matching child elements under the current node (supports label names or XPath paths). The following is a simple but complete example to demonstrate how to use findall() .

? Basic usage: findall() finds multiple elements

Suppose we have the following XML file (save as books.xml ):

 <library>
    <book id="1">
        <title>Python Crash Course</title>
        <author>Eric Matthes</author>
        <price>29.99</price>
    </book>
    <book id="2">
        <title>Fluent Python</title>
        <author>Luciano Ramalho</author>
        <price>45.00</price>
    </book>
    <book id="3">
        <title>Learning XML</title>
        <author>Erik T. Ray</author>
        <price>39.95</price>
    </book>
</library>

? Sample code: Read and find all titles and authors

 import xml.etree.ElementTree as ET

# Load XML file tree = ET.parse('books.xml')
root = tree.getroot()

# Use findall() to find all book elements books = root.findall('book')

# traverse each book element and extract information for book in books:
    title = book.find('title').text # find() Get the first matching child element author = book.find('author').text
    price = book.find('price').text
    book_id = book.get('id') # Get the attribute print(f"ID: {book_id}, Title: {title}, Author: {author}, Price: ${price}")

Output result:

 ID: 1, Title: Python Crash Course, Author: Eric Matthes, Price: $29.99
ID: 2, Title: Fluent Python, Author: Luciano Ramalho, Price: $45.00
ID: 3, Title: Learning XML, Author: Erik T. Ray, Price: $39.95

? findall() supports XPath subsets (common techniques)

You can use a simple XPath expression in findall() :

 # Find all prices > 40 books (Note: ElementTree does not support conditional filtering syntax, it needs to be judged manually)
for book in root.findall('book'):
    price = float(book.find('price').text)
    if price > 40:
        print(book.find('title').text, f"(${price})")

# Output:
# Fluent Python ($45.0)

?? Note: ElementTree 's findall() only supports limited XPath syntax, such as:

• tag : direct child element
• tag/subtag
• ./tag
• * Wildcard
• Basic paths such as [@attribute]

For example:

 # Find all books with id attributes
books_with_id = root.findall('book[@id]')

# Find all title elements (no matter how deep the nesting is, './/title' is available)
all_titles = root.findall('.//title') # Similar to //title in XPath

? Summary: Comparison of common methods

Example:

 first_book = root.find('book') # first book
titles = root.findall('book/title') # All title elements all_authors = [a.text for a in root.findall('book/author')]

Basically that's it. findall() is one of the most commonly used tools for processing batch XML data. It can easily extract structured information with find() and attribute access.

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