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Date: Sat, 21 Jan 2012 13:47:00 +0000
From: Andrea Crotti <andrea.crotti.0@gmail.com>
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Subject: while True or while 1
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:19188

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