Oddity with function default arguments

[Sheila King]

Here is something that surprised me tonight:
[color=blue][color=green][color=darkred]
>>> def myfunc(x, y, a='A', *mylist):[/color][/color][/color]
print x
print y
print a
for item in mylist:
print item

[color=blue][color=green][color=darkred]
>>> myfunc(2, 5, 6, 7, 8)[/color][/color][/color]
2
5
6
7
8[color=blue][color=green][color=darkred]
>>> myfunc(1, 2)[/color][/color][/color]
1
2
A[color=blue][color=green][color=darkred]
>>> myfunc(1, 2, 3, 4, 5)[/color][/color][/color]
1
2
3
4
5[color=blue][color=green][color=darkred]
>>> def myfunc(x, y, *mylist, a='A'):[/color][/color][/color]

SyntaxError: invalid syntax

Why isn't the default value for a printing out when I include list
arguments?

(This is Python 2.2.2 (#37, Oct 14 2002, 17:02:34) [MSC 32 bit (Intel)] on
win32, if that makes a difference.)

I would suspect at first a Python bug, but maybe I'm just not "seeing"
something that I should?

--
Sheila King

http://www.thinkspot.net/sheila/

http://www.k12groups.org/

[Erik Max Francis]

Re: Oddity with function default arguments

Sheila King wrote:
[color=blue]
> SyntaxError: invalid syntax
>
> Why isn't the default value for a printing out when I include list
> arguments?[/color]

The remaining arguments (*) or remaining keyword arguments (**) go at
the end of the argument list.

--
__ Erik Max Francis && max@alcyone.com && http://www.alcyone.com/max/
/ \ San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
\__/ Did you ever love somebody / Did you ever really care
-- Cassandra Wilson

[Heiko Wundram]

Re: Oddity with function default arguments

Am Samstag, 12. Juni 2004 09:05 schrieb Sheila King:[color=blue]
> Why isn't the default value for a printing out when I include list
> arguments?[/color]

You don't include list arguments. You just put positional arguments into a
function call, and of course a positional argument at the position of the
argument which has a default declared gets inserted there, that's why you
don't see the A when you pass more than two arguments.

All remaining positional arguments (once the named positional arguments have
been filled) get put into the list *mylist, which is commonly called *args
(it's not a list, btw., it's a tuple), which in your case are all arguments
behind the third.

Hope this makes this somewhat clearer...

Heiko.