Make an Argument Optional in Python

Question

I'm making a Script with a GUI Box in a CAD program, and the User selects about 7 different surfaces in the viewport. I then pass those values onto another Function when the User hits "OK"

The function that it is passed to looks like this

def MeshingTools(od_idSurf, trgSurf, PipeBodySurf, sealSurf, threadSurf, BodySurf, cplgEndSurf):

The problem is: if the user does not need to select one of those surfaces, I get a error saying, MeshingTools() takes exactly 7 non-keyword arguments (2 given)

How can I get around this issue?

UPDATE:

I tried keyword arguments and am not quite getting what I need.

def MeshingTools(**kwargs): print kwargs

When I just select 1 surface, I get the following out

{'PipeBodySurf': (mdb.models['FullCAL4'].rootAssembly.instances['PinNew-1'].edges[151], mdb.models['FullCAL4'].rootAssembly.instances['PinNew-1'].edges[153])}

if I try to print PipeBodySurf , it says that global name is not defined.

Any ideas?

FINAL UPDATE (SOLVED)

Now I see that **kwargs creates a dictionary, so instead of using just the parameter name in the rest of the code, you have to use kwargs['parameter'] and then it will use the values

Have you tried pasting your question's title into a Google search? — TigerhawkT3, Jun 18 '15 at 19:21
TigerhawkT3, yeah, but I could only find where you can overwrite the values, not what I want — SoljaragCNC, Jun 18 '15 at 19:23
If keyword arguments don't meet your needs, you need to tell us what you've tried and what you didn't like about them. — John Kugelman, Jun 18 '15 at 19:28
I guarantee you that this information was readily available. If you don't want your code to overwrite values, don't tell it to. You might be well-served by looking into the [official Python tutorial](https://docs.python.org/3.4/tutorial). — TigerhawkT3, Jun 18 '15 at 19:28
John, yeah, keyword arguments looks like they will work.... going to try it soon — SoljaragCNC, Jun 18 '15 at 19:31
ok, keyword arguments are not quite working... please look at my updated question — SoljaragCNC, Jun 18 '15 at 20:39

Mazdak · Accepted Answer · 2015-06-18T19:24:47.447

1

You can use arbitrary argument passing with * operation :

def MeshingTools(*args):
  for i in args:
      #do stuff with i

Functions can use special argument preceded with one or two * character to collect an arbitrary number of extra arguments. (* for positional arguments and ** for keyword arguments)

edited Jun 18 '15 at 19:24

answered Jun 18 '15 at 19:18

Mazdak

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people should lose 100 points for downvoting without comment. WHY the downvote?! – Chris Hawkes Jun 18 '15 at 19:20
The answer is rather barebones. Keyword arguments should be mentioned, if not preferred. – John Kugelman Jun 18 '15 at 19:21
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@JohnKugelman Yeah you are right just added! – Mazdak Jun 18 '15 at 19:25
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@ChrisHawkes Thanks, I should mentioned about keyword arguments too. – Mazdak Jun 18 '15 at 19:27

Make an Argument Optional in Python

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