[Tutor] What is __weakref__ ?

[bob gailer]

On 1/18/2011 8:08 AM, Karim wrote:
>
> I know this is ugly but until now it is the only way (with this side 
> effect) I found to declare Enums class that I _understand_:
>
> *class CategoryType(object):
>     """Implements the enumeration and prevent associated newly created
>     instances to redefine enums value via special class variable 
> '__slots__'
>     definition. It makes also, instances have no attributes at all.
>     """
>     __slots__ = ()
>
>     TRANSISTOR, MOS, BIPOLAR, CAPACITOR, RESISTOR, DIODE, ESD, PAD, \
>     COMPARATOR, OPAMP, ADC, DAC, PLL, OTHER = range(14)
>
>     def toString ( self, litteral ):
>         """Convert the litteral integer number to its associated 
> string representation."""
>         if litteral == self.TRANSISTOR:
>           return 'transistor'
>         elif litteral == self.MOS:
>           return 'mos'
>         elif litteral == self.BIPOLAR:*
> [...]
IMHO this just cries out for a dictionary:

class CategoryType(object):
   __slots__ = ()
   enums = {
     0: 'transistor',
     1: 'mos',
     ...
     }
   def toString(self, literal):
     """Convert the literal integer number to its associated string 
representation."""
     return self.enums[literal]

Note this does not handle invalid literal.

If you are happy with range 14) you could alternatively use a list:
   enums = ['transistor, 'mos',  ...]

-- 
Bob Gailer
919-636-4239
Chapel Hill NC

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