W3Schools XPath Examples using Python and lxml

A Python w3schools XPath Example.md

A Python w3schools XPath Example

The w3schools XPath Examples are PRETTY GREAT.

However they are implemented using JavaScript. I mostly use Python so I thought I'd try to mimic the output using Python 3.10 with lxml on Windows 10.

1. Put the books.xml file in the same directory as the w3BooksTest.py .
2. Run with Python 3.10 on Windows with lxml installed

books.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- from https://www.w3schools.com/xml/xpath_examples.asp  -->
<bookstore>

<book category="cooking">
  <title lang="en">Everyday Italian</title>
  <author>Giada De Laurentiis</author>
  <year>2005</year>
  <price>30.00</price>
</book>

<book category="children">
  <title lang="en">Harry Potter</title>
  <author>J K. Rowling</author>
  <year>2005</year>
  <price>29.99</price>
</book>

<book category="web">
  <title lang="en">XQuery Kick Start</title>
  <author>James McGovern</author>
  <author>Per Bothner</author>
  <author>Kurt Cagle</author>
  <author>James Linn</author>
  <author>Vaidyanathan Nagarajan</author>
  <year>2003</year>
  <price>49.99</price>
</book>

<book category="web">
  <title lang="en">Learning XML</title>
  <author>Erik T. Ray</author>
  <year>2003</year>
  <price>39.95</price>
</book>

</bookstore>

w3BooksTest.py

# -*- coding: utf-8 -*-
r"""w3BooksTest.py    Tests the W3Schools  XPath Examples using Python-Lxml and .\byLXMLcopy\books.xml
Usage:   ./w3BooksTest.py 
Sample:  ./w3BooksTest.py 
see:     [XPath Examples](https://www.w3schools.com/xml/xpath_examples.asp)
  [lxml >> Parsing from strings and files](https://lxml.de/tutorial.html#parsing-from-strings-and-files)
  [The lxml.etree Tutorial](https://lxml.de/tutorial.html)
"""
import os, sys
import lxml.etree   # N.B. import lxml   then using  lxml.etree  DOESN'T WORK

def w3BooksTest():
    """
    use python to mimic the w3schools [XPath Examples](https://www.w3schools.com/xml/xpath_examples.asp)
    [github gist - sekineh/python3_lxml.md](https://gist.github.com/sekineh/f4638c55df2f3e7f28a04a1fa9ea53d9)  `body = tree.xpath('//body')`
    """
    # [github gist - sekineh/python3_lxml.md](https://gist.github.com/sekineh/f4638c55df2f3e7f28a04a1fa9ea53d9)  `body = tree.xpath('//body')`
    tree = lxml.etree.parse('books.xml')   # (some_file_or_file_like_object)

    print()
    path = "/bookstore/book/title"
    titles = tree.xpath(path) # https://www.w3schools.com/xml/tryit.asp?filename=try_xpath_select_cdnodes
    print('type(titles): %s'%(type(titles)))
    print('titles: %s'%(titles))

    print()
    # equivalent of [XPath Examples](https://www.w3schools.com/xml/xpath_examples.asp)
    for t in titles:
        print('t.text: %s'%(t.text))      # Just a guess   but it WORKED!

    print()
    print("""let's try the next w3schools example == "/bookstore/book[1]/title" """)
    xpath = "/bookstore/book[1]/title"
    resultL = tree.xpath(xpath) 
    print('resultL[0].text: %s'%(resultL[0].text))
    
    print()
    print("""next example  Select all the prices == "/bookstore/book/price[text()]" """)
    xpath = "/bookstore/book/price[text()]"
    resultL = tree.xpath(xpath) 
    for r in resultL:
        print('r.text: %s'%(r.text))      
    
    print()
    print("""next example  Select price nodes with price>35 == "/bookstore/book[price>35]/price" """)
    xpath = "/bookstore/book[price>35]/price"
    resultL = tree.xpath(xpath) 
    for r in resultL:
        print('r.text: %s'%(r.text))      
    
    print()
    print("""next example  Select *title* nodes with price>355 == "/bookstore/book[price>35]/title" """)
    xpath = "/bookstore/book[price>35]/title"
    resultL = tree.xpath(xpath) 
    for r in resultL:
        print('r.text: %s'%(r.text))      
    

def main():
    print('ORIG os.getcwd(): %s'% ( os.getcwd() ) )
    print('__file__:    %s'% ( __file__ ) )
    print('dirpath(__file__):    %s'% ( os.path.split(__file__)[0]  ) )
    print('__name__:    %s'% ( __name__ ) )
    os.chdir(os.path.split(__file__)[0])
    print('NEW os.getcwd(): %s'% ( os.getcwd() ) )
    w3BooksTest()
if __name__ == '__main__':
    main()