XmlDocument Parse scientific notation in xpath attribute value to a number

I have XML where the values are saved in scientific notation and I need to preform some comparisons on that value . But the scientific notation numbers are not working as expected.

Below is the code I have:

XmlDocument doc = new XmlDocument();
doc.LoadXml("<MainLevel><SubLevel Name=\"test\"  Amount=\"0.0E0\"></SubLevel></MainLevel>");
    
XmlNodeList? xmlLevelsList1 = doc.SelectNodes("MainLevel/SubLevel[@Amount<=275.00]");// this does not return anything because 0.0E0 is in scientific notation                
doc.LoadXml("<MainLevel><SubLevel Name=\"test\"  Amount=\"0.00\"></SubLevel></MainLevel>");

XmlNodeList? xmlLevelsList2 = doc.SelectNodes("MainLevel/SubLevel[@Amount<=275.00]"); this does not return anything because 0.00 is a good format

I want xmlLevelsList1 to return 1 node instead of 0. It is returning 0 because

> "0.0E0" is not a valid number.

It is better to use LINQ to XML API. It is available in the .Net Framework since 2007.

As @zx485 already pointed out: "XSLT 1.0 does not have support for scientific notation."

So, we cannot use an XPath expression.

Converting to a double data type on the .Net side does the job.

c#

void Main()
{
	XDocument doc = XDocument.Parse(@"<MainLevel>
			<SubLevel Name='test' Amount='0.0E0'></SubLevel>
			<SubLevel Name='test1'  Amount='10.0E1'></SubLevel>
		    <SubLevel Name='test1'  Amount='4.0E5'></SubLevel>
		    <SubLevel Name='test1'  Amount='2.75E2'></SubLevel>
		    <SubLevel Name='test1'  Amount='2.76E2'></SubLevel>
		</MainLevel>");
	
	var xmlLevelsList1 = doc.Descendants("SubLevel")
		.Where(d => double.Parse(d.Attribute("Amount").Value) <= 275.00);
	Console.WriteLine(xmlLevelsList1);
}

Output

<SubLevel Name="test" Amount="0.0E0"></SubLevel>
<SubLevel Name="test1" Amount="10.0E1"></SubLevel>
<SubLevel Name="test1" Amount="2.75E2"></SubLevel>

The number() function can be used in XPath 1.0

/MainLevel/SubLevel[number(@Amount) <= 275.00]

Given

<?xml version="1.0" encoding="utf-8" ?>
<MainLevel>
    <SubLevel Name="test"  Amount="0.0E0"></SubLevel>
    <SubLevel Name="test1"  Amount="10.0E1"></SubLevel>
    <SubLevel Name="test1"  Amount="4.0E5"></SubLevel>
    <SubLevel Name="test1"  Amount="2.75E2"></SubLevel>
    <SubLevel Name="test1"  Amount="2.76E2"></SubLevel>
</MainLevel>

Will return

<SubLevel Name="test" Amount="0.0E0"/>
<SubLevel Name="test1" Amount="10.0E1"/>
<SubLevel Name="test1" Amount="2.75E2"/>

Tested with xmllint that uses libxml2

 xmllint --xpath '/MainLevel/SubLevel[number(@Amount) <= 275.00]' tmp.xml
<SubLevel Name="test" Amount="0.0E0"/>
<SubLevel Name="test1" Amount="10.0E1"/>
<SubLevel Name="test1" Amount="2.75E2"/>

Testing with python lxml

from lxml import etree
tree = etree.parse("tmp.xml")
[e.get('Amount') for e in tree.xpath('/MainLevel/SubLevel[number(@Amount) <= 275.00]')]
['0.0E0', '10.0E1', '2.75E2']

Using Saxon.NET:

using System.Xml;
using Saxon.Api;

XmlDocument doc = new XmlDocument();
doc.LoadXml("<MainLevel><SubLevel Name=\"test\"  Amount=\"0.0E0\"></SubLevel></MainLevel>");
    
XmlNodeList? xmlLevelsList1 = doc.SelectNodes("MainLevel/SubLevel[@Amount<=275.00]");// this does not return anything because 0.0E0 is in scientific notation                

Console.WriteLine(xmlLevelsList1.Count);

Processor processor = new Processor();

var docBuilder = processor.NewDocumentBuilder();

var xdmDoc = docBuilder.Wrap(doc);

var xpathCompiler = processor.NewXPathCompiler();

var xdmResult = xpathCompiler.Evaluate("MainLevel/SubLevel[@Amount<=275.00]", xdmDoc);

Console.WriteLine(xdmResult.Count);

Output:

0
1

Do note that, while you can run XPath 3.1 against the Microsoft DOM (i.e. XmlDocument/XmlNode) that Saxon has its own tree model and it is recommended to only use the Microsoft DOM if you have legacy code where you can't switch to Saxon's native tree model.