[Python-ideas] "on" statement

[MRAB]

Bruce Leban wrote:
> I think this is a great idea, but I would not want to introduce a new 
> keyword. How about
> 
>     foo is in bar     = hasattr(foo,bar)
>     foo is not in bar = not hasattr(foo,bar)
> 
> But there are other common checks I do all the time that I would really 
> like to have shortcuts for. Here are ways to do them without new keywords:
> 
>     foo is class bar = isinstance(foo,bar)

To me, this is asking whether 'foo' is a class. Better would be:

     foo in class bar

>     foo is from bar  = issubclass(foo,bar)

Perhaps:

     foo from class bar

(although I'm not happy with it.)

>     foo is with bar  = type(foo) == type(bar)
> 
> Can we make an exception to the moratorium, just for today?
> 
Only for foolish ideas. :-)

> --- Bruce
> http://www.vroospeak.com
> 
> 
> On Thu, Apr 1, 2010 at 8:15 AM, Robert Madole <robmadole at gmail.com 
> <mailto:robmadole at gmail.com>> wrote:
> 
>     So I just wrote my 1-gazillionth "if hasattr('method', my_object):"
>     and wanted badly to write this.
> 
>            if 'method' on my_object:
> 
>     I'm not the most experienced Python user, but as far as I can tell
>     hasattr is the preferred way of checking if a method exists.
> 
>     Please correct me if there is a better way, otherwise I'd like to
>     see what everyone thinks about an "on" statement being added to the
>     Python language.
> 
>     Thanks,
> 
>     Rob Madole
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