missing 'xor' Boolean operator

[Ethan Furman]

Robert Kern wrote:
> On 2009-07-14 14:56, Dr. Phillip M. Feldman wrote:
> 
>> != does do what I want, except that it doesn't indicate to someone 
>> reading
>> the code that the operands are being treated as logicals.  
>> (Readability is
>> supposed to be one of the major selling points of Python).  But, this is
>> probably good enough.
> 
> 
> In the words of those greater than myself, "Not every one-liner needs to 
> be in the standard library."
> 
> def xor(a, b):
>     return bool(a) != bool(b)
> 

Let's see...

   and returns the last object that is "true"
   or  returns the first object that is "true"

so should xor return the only object that is "true", else False/None?

def xor(a, b)
     if a and b:
         return None
     elif a:
         return a
     elif b:
         return b
     else:
         return None

~Ethan~