need help with properties

Esmail ebonak at hotmail.com
Sat May 9 18:05:33 CEST 2009


hi Scott,

Scott David Daniels wrote:
> Esmail wrote:
>> I am just reading about properties in Python. I am thinking
>> of this as an indirection mechanism, is that wrong? If so, how
>> come the getter/setters aren't called when I use properties
>> instead of the functions directly?
> Because you weren't actually using them.  You were writing:
>     size = 3, 7
> not:
>     r.size = 3, 7

duh!! .. I knew it had to be something sill .. how do I represent
a red face in ASCII ? ;) I was concentrating so much on the new
feature I totally didn't see this.

I appreciate your code with annotations, helpful.

>         def setSize(self, shape): # a setter takes a single arg
>             width, height = shape
>             print 'in setter'
>             if width < 0 or height < 0:
>                 print >> sys.stderr, 'Negative values not allowed'
>             else:
>                 self._width = width
>                 self._height = height

>     r.setSize((-40, 30))

Just curious, is there a way to pass more than one arg to a setter, or
do we always have use some sort of unpacking at the other end?

Thanks,

Esmail




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