function with list argument defaulting to [] - what's going on here???

[Tim Leslie]

On 14 Apr 2007 20:20:42 -0700, Paddy <paddy3118 at googlemail.com> wrote:
> On Apr 15, 3:58 am, Steven D'Aprano
> <s... at REMOVE.THIS.cybersource.com.au> wrote:
> > On Sat, 14 Apr 2007 17:33:11 -0800, Troy Melhase wrote:
> > > On 4/14/07, Mike <m... at woh.rr.com> wrote:
> > >> While trying to write a recursive function involving lists, I came
> > >> across some (to me) odd behavior which I don't quite understand. Here's
> > >> a trivial function showing the problem.
> >
> > > fromhttp://docs.python.org/ref/function.html:
> >
> > > Default parameter values are evaluated when the function definition is
> > > executed. This means that the expression is evaluated once, when the
> > > function is defined, and that that same ``pre-computed'' value is used
> > > for each call. This is especially important to understand when a
> > > default parameter is a mutable object, such as a list or a dictionary:
> > > if the function modifies the object (e.g. by appending an item to a
> > > list), the default value is in effect modified.
> >
> > This comes up so often that I wonder whether Python should issue a warning
> > when it sees [] or {} as a default argument.
> >
> > What do people think? A misuse or good use of warnings?
> >
> > --
> > Steven.
>
> I wonder if it is a check done by Pylint or PyChecker?

It is a check done by pylint

Tim

>
> - Paddy.
>
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