How to transform an XML file using XSLT in Python?

Using lxml,

import lxml.etree as ET

dom = ET.parse(xml_filename)
xslt = ET.parse(xsl_filename)
transform = ET.XSLT(xslt)
newdom = transform(dom)
print(ET.tostring(newdom, pretty_print=True))

LXML is a widely used high performance library for XML processing in python based on libxml2 and libxslt - it includes facilities for XSLT as well.

The best way is to do it using lxml, but it only support XSLT 1

import os
import lxml.etree as ET

inputpath = "D:\\temp\\"
xsltfile = "D:\\temp\\test.xsl"
outpath = "D:\\output"


for dirpath, dirnames, filenames in os.walk(inputpath):
            for filename in filenames:
                if filename.endswith(('.xml', '.txt')):
                    dom = ET.parse(inputpath + filename)
                    xslt = ET.parse(xsltfile)
                    transform = ET.XSLT(xslt)
                    newdom = transform(dom)
                    infile = unicode((ET.tostring(newdom, pretty_print=True)))
                    outfile = open(outpath + "\\" + filename, 'a')
                    outfile.write(infile)

to use XSLT 2 you can check options from Use saxon with python