Re: checking if a list is empty

From	Terry Reedy <tjreedy@udel.edu>
Subject	Re: checking if a list is empty
Date	2011-05-14 17:29 -0400
References	(10 earlier) <d72b37d6-bf1e-4cec-94e3-88baca894fd9@35g2000prp.googlegroups.com> <mailman.1548.1305380575.9059.python-list@python.org> <a86edee8-306b-4777-99fb-99895b512ef6@k15g2000pri.googlegroups.com> <mailman.1551.1305388537.9059.python-list@python.org> <311327ac-2593-44d7-b19d-32533af87d4b@x38g2000pri.googlegroups.com>
Newsgroups	comp.lang.python
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On 5/14/2011 1:43 PM, rusi wrote:

> But it seems you did not get the moral? Spelt out: "Beware of lossy
> compression!"
> [Which is also the moral of my 'proof']

I get it now. As I suggested in response to Stephen, [] and [1] spell 
False and True only in boolean contexts (if/while headers) where they 
are implicitly wrapped with a bool() call, which is to say, where their 
boolean value is extracted from them. As you point out, there is 
information loss as all other context-irrelevant details are ignored.

-- 
Terry Jan Reedy

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Re: checking if a list is empty Hans Georg Schaathun <hg@schaathun.net> - 2011-05-11 10:02 +0100
  Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-11 12:14 +0000
    Re: checking if a list is empty Hans Georg Schaathun <hg@schaathun.net> - 2011-05-11 15:05 +0100
      Re: checking if a list is empty "D'Arcy J.M. Cain" <darcy@druid.net> - 2011-05-11 10:27 -0400
        Re: checking if a list is empty Hans Georg Schaathun <hg@schaathun.net> - 2011-05-11 18:59 +0100
          Re: checking if a list is empty alex23 <wuwei23@gmail.com> - 2011-05-11 20:16 -0700
            Re: checking if a list is empty Hans Georg Schaathun <hg@schaathun.net> - 2011-05-12 06:20 +0100
      Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-11 15:50 +0000
        Re: checking if a list is empty Chris Angelico <rosuav@gmail.com> - 2011-05-12 02:05 +1000
          Re: checking if a list is empty Hans Georg Schaathun <hg@schaathun.net> - 2011-05-11 18:56 +0100
            Re: checking if a list is empty harrismh777 <harrismh777@charter.net> - 2011-05-11 16:13 -0500
    RE: checking if a list is empty "Prasad, Ramit" <ramit.prasad@jpmchase.com> - 2011-05-11 13:39 -0400
  Re: checking if a list is empty Roy Smith <roy@panix.com> - 2011-05-11 08:26 -0400
    Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-11 13:29 +0000
    Re: checking if a list is empty Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-05-12 17:44 +1200
      Re: checking if a list is empty Hans Georg Schaathun <hg@schaathun.net> - 2011-05-12 07:06 +0100
      Re: checking if a list is empty Roy Smith <roy@panix.com> - 2011-05-12 07:36 -0400
        Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-13 00:16 +0000
          Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-12 23:46 -0700
            Re: checking if a list is empty Chris Rebert <clp2@rebertia.com> - 2011-05-13 01:02 -0700
              Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-13 03:58 -0700
            Re: checking if a list is empty Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-05-14 14:34 +1200
              Re: checking if a list is empty David Robinow <drobinow@gmail.com> - 2011-05-14 10:28 -0400
                Re: checking if a list is empty Roy Smith <roy@panix.com> - 2011-05-14 11:04 -0400
            Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-14 07:39 +0000
              Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-14 00:45 -0700
                Re: checking if a list is empty Chris Angelico <rosuav@gmail.com> - 2011-05-14 23:42 +1000
                Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-14 08:47 -0700
                Re: checking if a list is empty Chris Angelico <rosuav@gmail.com> - 2011-05-15 01:55 +1000
                Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-14 10:43 -0700
                Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-14 17:29 -0400
                Re: checking if a list is empty Ben Finney <ben+python@benfinney.id.au> - 2011-05-15 09:26 +1000
                Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-14 19:41 -0700
                Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-15 05:07 +0000
                Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-15 10:33 -0700
                Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-15 17:36 -0400
                Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-15 22:56 -0700
                Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-16 00:36 +0000
                Re: checking if a list is empty harrismh777 <harrismh777@charter.net> - 2011-05-15 20:59 -0500
                Re: checking if a list is empty rusi <rustompmody@gmail.com> - 2011-05-15 22:40 -0700
                Re: checking if a list is empty harrismh777 <harrismh777@charter.net> - 2011-05-15 20:25 -0500
                Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-15 21:57 -0400
                Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-14 16:59 -0400
                Re: checking if a list is empty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-15 05:00 +0000
              Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-14 16:53 -0400
    Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-12 15:37 -0400
    Re: checking if a list is empty Terry Reedy <tjreedy@udel.edu> - 2011-05-12 18:00 -0400

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