tixiGetNumberOfChilds gives 1 for an empty list

[spookyGh0st]

For the xml file:

<?xml version="1.0" encoding="utf-8"?>
<project>
  <elements>
  </elements>
</project>

And the corresponding function call:

int count;
tixiGetNumberOfChilds(handle,"project/elements",&count);

we get 1 and not as I would expect to 0. Is this intentional, and if so, how would one get the actual list size?

[ArneBachmannDLR]

Confirmed for Python:

> set PATH=C:\Users\bach_ar\Downloads\TIXI-3.3.0-win64\bin;%PATH%
> python
import tixi3wrapper
cpacs = tixi3wrapper.Tixi3()
cpacs.openString("""?xml version="1.0" encoding="utf-8"?>
<project>
  <elements>
  </elements>
</project>""")
cpacs.getNumberOfChilds("/project/elements")
1

I can fix it by removing the newline and spaces between <element> and </element>.
It seems that tixi counts the space as an element somehow.

[rainman110]

Spaces and new Lines constitute technically to (invisible) XML text elements, so that's why you'll get "1" as the number of childs. So technically (by xml definition), the result 1 is correct. I understand though, that in this case, you want probably iterate over the "element" nodes, so you expect a zero count.

I think a better API would be something

tixiGetNumberOfChildElements(handle, "/project/elements", "element", &count)

where you explicitly need to defined the element name you are searching for.

You can though use the function tixiXPathEvaluateNodeNumber instead, to query only for "element" nodes:

tixiXPathEvaluateNodeNumber(handle, "/project/elements//element", &count)

[rainman110]

Here's an example

from tixi3 import tixi3wrapper

cpacs = tixi3wrapper.Tixi3()
cpacs.openString("""<?xml version="1.0" encoding="utf-8"?>
<project>
  <elements>
  </elements>
</project>""")

# prints 0
print(cpacs.xPathEvaluateNodeNumber("/project/elements//element"))

cpacs = tixi3wrapper.Tixi3()
cpacs.openString("""<?xml version="1.0" encoding="utf-8"?>
<project>
  <elements>
    <element/>
  </elements>
</project>""")

# prints 1
print(cpacs.xPathEvaluateNodeNumber("/project/elements//element"))

[CLiersch]

I guess, this would be equivalent to the
ReturnCode tixiGetNamedChildrenCount (const TixiDocumentHandle handle, const char *elementPath, const char *childName, int *count)
method, right?

[rainman110]

@CLiersch You are absolutely right 🤦 . It seems, that it is too long ago, since I was using tixi last time.

[rainman110]

I am closing the issue, since the function is doing what it should do. Use instead tixiGetNamedChildrenCount as @CLiersch suggested.

[joergbrech]

Thanks for your input! I moved this issue to the discussion board.