XPath Query scenarios to Select Nodes in XML Using lxml in Python 3.9
I'm experimenting with I'm maintaining legacy code that I'm trying to use XPath to select specific nodes in an XML document with the `lxml` library in Python 3.9, but my query is returning an empty result set. Here's a snippet of the XML I'm working with: ```xml <root> <item id="1"> <name>Item One</name> <value>100</value> </item> <item id="2"> <name>Item Two</name> <value>200</value> </item> </root> ``` I want to select all `<item>` nodes where the `<value>` is greater than 150. My XPath expression looks like this: ```python from lxml import etree xml_string = '''<root>\ <item id="1">\ <name>Item One</name>\ <value>100</value>\ </item>\ <item id="2">\ <name>Item Two</name>\ <value>200</value>\ </item>\ </root>'''\ root = etree.fromstring(xml_string) items = root.xpath('//item[value > 150]') print(items) ``` However, when I run this code, I get an empty list as a result. I've also tried using `//item[value="200"]` to see if it was an scenario with the operator, but that didn't return anything either. I suspect that it might be related to the fact that the `<value>` node is a child of `<item>` and I'm not referencing it correctly in the XPath. Additionally, I noticed that I often get confused with namespaces in XML, but my XML is not using any namespaces. Can someone guide to understand what I'm doing wrong with my XPath query? Is there a more efficient way to select nodes based on their child elements? I'm also aware of potential performance optimization if the XML grows larger, so I'm looking for best practices as well. I'm coming from a different tech stack and learning Python. Has anyone dealt with something similar? I'd be grateful for any help.