Somthing strange with list as default argument

[Alex Martelli]

Julien Sagnard <julien.sagnard.withoutthis at free.fr> wrote:

> Hi all,
> 
> When passing a list as default argument for a function, only one list is
> created for all calls.

Right.

> I'm not found any reference of this. Is it a bug ?

No, you just didn't look in the right places, for example in the
Tutorial which is the recommended first reading for new Python users.

Under 4.7.1 the Tutorial says:

"""
Important warning: The default value is evaluated only once. This makes
a difference when the default is a mutable object such as a list,
dictionary, or instances of most classes.
"""

The 'Important warning' is in bold, too...


Alex