Re: [PyMOL] Python Function with Unlimited Positional Arguments

[Warren D. <wa...@de...>]

Sean,

You need a keyword argument list as well, so that the effective PyMOL
class instance (_self) can be passed in by keyword (actual use of _self
is only strictly required when you have multiple PyMOLs active in a
single Python interpreter).

# pml input:

python
 
def my_fn(*arg, **kwd):
   print arg

cmd.extend("my_fn", my_fn)

python end

my_fn my_arg_1, my_arg_2

# PyMOL output:

('my_arg_1', 'my_arg_2') 

Cheers,
Warren

________________________________

	From: Sean Law [mailto:mag...@ho...] 
	Sent: Sunday, August 02, 2009 10:56 AM
	To: pym...@li...
	Subject: [PyMOL] Python Function with Unlimited Positional
Arguments
	
	
	Hi PyMOLers,
	
	I am trying to write a python script that will allow a user to
provide an unlimited number of positional arguments for a function.  I
am use to the following scheme for defining a function and its
arguments:
	
	def some_function ( x, y, z, file="false"):
	
	#DO SOMETHING
	
	return
	
	Where x, y, and z are required arguments and "file=false" is an
optional argument.  I came across the following page pertaining to
Python:
	
	
http://www.linuxtopia.org/online_books/programming_books/python_programm
ing/python_ch15s09.html
	
	See "Unlimited Number of Positional Arguments Values"
	
	There it explains that one could use the following syntax:
	
	def some_function ( *args):
	
	    print arg[0]
	
	return
	
	Now, when put this in a script and call the function in PyMOL it
spits out the following error:
	
	Traceback (most recent call last):
	  File "/pymol/./modules/pymol/parser.py", line 254, in parse
	    self.result=apply(layer.kw[0],layer.args,layer.kw_args)
	TypeError: some_function() got an unexpected keyword argument
'_self'
	
	Is the "*args" method simply not possible in PyMOL?  I tried
using "**args" which worked nicely for keyword arguments.
	
	Any help would be greatly appreciated.  Thank you for your time.
	
	Sean
	
	
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