Reference gotcha

[Ed Schofield]

Hi all,
This interested me:

>>> a1 = a2 = {}
>>> a1['blah'] = 1
>>> a2
{'blah': 1}
>>> a1 == a2
True


Whereas ...


>>> b1 = b2 = 0
>>> b1 += 1
>>> b2
0
>>> b1 == b2
False

So how should one create a robust alias for a numeric type?

This bit me when I was trying to do the following in a class:
	def __init__(self, data):
		a = self.a = {}
		b = self.b = {}
		c = self.c = 0

		# and increment them here ...

Best regards,
Ed Schofield