Re: [Tutor] Defining "bit" type

[bob gailer]

Vicent wrote: Hello. As fas as I know, there is a "bytes" type in Python 3, which is a sequence of bytes. Anyway, I am working with Python 2.5.4, and I am interested in defining a new type called "bit" (if possible), which represents a number that can only take values 0 or 1 —that's what we would call a "binary variable", in a Mathematical Programming context. I want to define that new data type within my code, so that I can use it in the same way I would use "int", "long" and "float" data types, for instance. The problem is: there is no way that I know of to add fundamental types to Python. Also realize that variables are dynamically typed - so any assignment can create a variable of a new type. That is why a = 0 results in an int. So one must resort, as others have mentioned, to classes. Framework (untested): class Bit:   _value = 0 # default   def __init__(self, value):     self._value = int(bool(value))   def getvalue(self):     return self._x   def setvalue(self, value):     self._x = int(bool(value))   value = property(getvalue, setvalue)   def __add__(self, other): # causes + to act as or     self._value |= other   def __mul__(self, other): # causes * to act as and     self._value &= other b = Bit(1) b.value # returns 1 b.value = 0 b.value # returns 0 b.value + 1 # sets value to 1 b.value * 0 # sets value to 0 -- Bob Gailer Chapel Hill NC 919-636-4239

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