Probably because of the fact it is possible to set True equal to False and
consequently then invalidate loop logic as presented below:
True = False
while True:
...
On the other hand `1' will always be evaluated as a constant.
Don't know, just guessing.
Matteo
On Jan/21, Andrea Crotti wrote:
> I see sometimes in other people code "while 1" instead of "while True".
> I think using True is more pythonic, but I wanted to check if there is
> any difference in practice.
>
> So I tried to do the following, and the result is surprising. For what
> I can see it looks like the interpreter can optimize away the 1 boolean
> conversion while it doesn't with the True, the opposite of what I
> supposed.
>
> Anyone can explain me why is that, or maybe is my conclusion wrong?
>
> def f1():
> while 1:
> pass
>
> def f2():
> while True:
> pass
>
> In [10]: dis.dis(f)
> 2 0 SETUP_LOOP 3 (to 6)
>
> 3 >> 3 JUMP_ABSOLUTE 3
> >> 6 LOAD_CONST 0 (None)
> 9 RETURN_VALUE
>
> In [9]: dis.dis(f1)
> 2 0 SETUP_LOOP 10 (to 13)
> >> 3 LOAD_GLOBAL 0 (True)
> 6 POP_JUMP_IF_FALSE 12
>
> 3 9 JUMP_ABSOLUTE 3
> >> 12 POP_BLOCK
> >> 13 LOAD_CONST 0 (None)
> 16 RETURN_VALUE
>
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>
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