I ran into a strange case.
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on win32
...
>>> -1 == True
False
>>> -1 == False
False
This works though:
>>> if -1:
print "OK"
OK
After some head scratching, I realized that:
- bool is a subclass of int and that True and False evaluates to 1 and 0, so -1 is equal to neither; and
- The if -1: statement probably works by treating -1 as bool(-1).
But I can't help finding the former comparison behavior odd. I admit that it is odd to write such code but when someone writes -1 == True, the intention is clearly a boolean comparison, not a numerical value comparison, isn't it?
As far as I understand, to do this comparison, python is casting (loosely speaking) True to its numerical value, rather than casting -1 to its boolean value.
So, my question is: wouldn't it make more sense to do just the opposite, i.e. cast -1 to its boolean value and do a boolean comparison of the operands, when one of the operands is True or False?
Or is this too fancy? What do you think?
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