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Re: count strangeness

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James Stroud wrote:

> Peter Otten wrote:
>> James Stroud wrote:
>>> WTF?
>> 
>> Put the code into a file, run it -- and be enlightened ;)
> 
> 
> tal 72% python2.7 eraseme.py
> 1
> 2
> 4
> 8tal 73% cat eraseme.py
> #! /usr/bin/env python
> 
> class C:
>    def __init__(self):
>      self.data = []
>    def doit(self, count=0):
>      for c in self.data:
>        count += c.doit(count)
>      count += 1
>      print count
>      return count
> 
> c = C()
> c.data.extend([C() for i in xrange(10)])
> c.doit()
> tal 74% python2.7 eraseme.py
> 1
> 2
> 4
> 8
> 16
> 32
> 64
> 128
> 256
> 512
> 1024
> 
> 
> Hmmm. It's still 1024.
> 
> What am I missing?
> 
> James

Like Chris I assumed that you wondered why 1024 appeared twice. It turns out 
WTF is not a got a good problem description.

Now for a complete run-through, the inner c.doit() has len(c.data) == 0, so 
count += c.doit(count) just adds count + 1 and you get 10 iterations:

(1) count=0, print 1, add 1
(2) count=1, print 2, add 2
(3) count=3, print 4, add 4
(4) count=7, print 8, add 8
(5) you get the idea

Another way to look at it: in your special case the inner loop can be 
rewritten as

for c in self.data:
    print count + 1
    count += count + 1

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count strangeness James Stroud <jstroud@mbi.ucla.edu> - 2011-05-21 23:02 -0700
  Re: count strangeness Chris Rebert <crebert@ucsd.edu> - 2011-05-21 23:27 -0700
    Re: count strangeness James Stroud <jstroud@mbi.ucla.edu> - 2011-05-21 23:32 -0700
      Re: count strangeness James Stroud <jstroud@mbi.ucla.edu> - 2011-05-21 23:39 -0700
      Re: count strangeness Chris Rebert <crebert@ucsd.edu> - 2011-05-21 23:55 -0700
        Re: count strangeness James Stroud <jstroud@mbi.ucla.edu> - 2011-05-22 00:03 -0700
  Re: count strangeness Peter Otten <__peter__@web.de> - 2011-05-22 08:31 +0200
    Re: count strangeness James Stroud <jstroud@mbi.ucla.edu> - 2011-05-21 23:34 -0700
      Re: count strangeness Peter Otten <__peter__@web.de> - 2011-05-22 09:13 +0200
    Re: count strangeness James Stroud <jstroud@mbi.ucla.edu> - 2011-05-21 23:56 -0700
  Re: count strangeness Roy Smith <roy@panix.com> - 2011-05-22 09:36 -0400

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