creating many similar properties
Michele Simionato
michele.simionato at gmail.com
Wed Oct 18 02:43:49 EDT 2006
Lee Harr wrote:
> I understand how to create a property like this:
>
> class RC(object):
> def _set_pwm(self, v):
> self._pwm01 = v % 256
> def _get_pwm(self):
> return self._pwm01
> pwm01 = property(_get_pwm, _set_pwm)
>
>
> But what if I have a whole bunch of these pwm properties?
>
> I made this:
>
> class RC(object):
> def _makeprop(name):
> prop = '_%s' % name
> def _set(self, v):
> v_new = v % 256
> setattr(self, prop, v_new)
> def _get(self):
> return getattr(self, prop)
> return property(_get, _set)
>
> pwm01 = _makeprop('pwm01')
> pwm02 = _makeprop('pwm02')
>
>
> Not too bad, except for having to repeat the name.
>
> I would like to just have a list of pwm names and
> have them all set up like that. It would be nice if
> each one was set to a default value of 127 also....
>
> Any thoughts?
>
Yes, what about this?
import sys
def defprop(name, default=127):
loc = sys._getframe(1).f_locals
prop = '_%s' % name
def _set(self, v):
v_new = v % 256
setattr(self, prop, v_new)
def _get(self):
return getattr(self, prop, default)
loc[name] = property(_get, _set)
class RC(object):
defprop('pwm01')
defprop('pwm02')
rc = RC()
print rc.pwm01 # 127
print rc.pwm02 # 127
rc.pwm02 = 1312
print rc.pwm02 # 32
This is a bit hackish, but I would prefer this over a metaclass
solution. since it does not add
any hidden magic to your class.
Michele Simionato
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