Parsing XML in GH Python Script Editor?

Rhino Developer
1

Tried to implement this in R5: https://docs.python.org/2/library/xml.etree.elementtree.html

to read and process http://www.canals.ny.gov/xml/liftbridges.xml

Code would be:
import xml.etree.ElementTree as ET
tree = ET.parse(‘country_data.xml’)
root = tree.getroot()

error: 1. Solution exception:expected str, got DataTree[object]

then tried:

from xml.etree import ElementTree # part of python distribution
from elementtree import SimpleXMLTreeBuilder # part of your codebase
ElementTree.XMLTreeBuilder = SimpleXMLTreeBuilder.TreeBuilder

with this error:

  1. Solution exception:No module named elementtree

gHowl has an xml parser to obtain the info, challenge is breaking it up into usable formats.

Referred to this example: https://discourse.mcneel.com/t/access-xml-data/1346/10

Wrote ths with y being the xml file path:
filename = y
xmldoc = System.Xml.XmlDocument()
xmldoc.Load(filename)
items = xmldoc.SelectNodes(“liftbridges/mile/”)
for item in items:
print item.InnerText

Not sure on best way to access it…

2

Hello,

I had a similar problem with Ironpython in Rhino 5. As I remember I ended up doing my xml parsing with a separate CPython script before importing the results into the Elk plugin.

I would be interested in an Ironpython solution…

1 Like
3

Hi @robe5177

This means that a DataTree[object] (a type that is very specific to the Grasshopper SDK) was fed to a library that only accepts str (strings) in that place.

Maybe there is a way to make this work: could you attach a small definition with something to test?

5

Ya: I can parse with the ET, but not with Steve’s Code. Probably some way to do it. Files to test:

Parsing_GH_R0
Parsing_GH_R01408×709 116 KB
liftbridges.xml (4.3 KB) Parse_GH_WIP_R0.gh (8.2 KB)

6

This works fine with both libraries in Rhino 6. Each can be used, and one is more “.Net”-y, and the other is more “classic Python”. Other than this, I don’t see any problem with any of them, and they give the same results.

image
image.png1254×707 100 KB

In Rhino 5, only the second one will work, because the old version of IronPython did not include the expat module.

I’ve attached a fuller example for both of these, applied to your XML.

for_robe5177.gh (9.7 KB)

Thanks,

Giulio

–
Giulio Piacentino
for Robert McNeel & Associates
giulio@mcneel.com

3 Likes
7

That’s great! thanks for writing up! Will test in v6 next week:)