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Re: Equivalent code to the bool() built-in function

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On Mon, Apr 18, 2011 at 10:22 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
>>>> types = [str, complex, float, bool]
>>>> [f(x) for f, x in zip(types, (1, 2, 3, 4))]
> ['1', (2+0j), 3.0, True]

I believe this one would work fine with a function defined as per OP -
zip takes callables, which could be types or functions.

> * if flags are written 0 and 1, that frequently fools people into
>  thinking they are meant to be understood as *integer* values rather
>  than boolean values, and they will do arithmetic on those flags;

Depending on what you mean by arithmetic, that can be a good thing.
I've frequently, in various languages, used booleans as though they
were integers - for instance, indexing a list with an integer plus a
condition. Contrived example:

mode = 2
...
print ("default", "default-root",
    "modeA","modeA-root",
    "modeB","modeB-root",
) [mode+mode+(uid==0)]

For debugging output, where I want to keep it as self-contained as
possible, constructs like these are very handy - especially as they
can be embedded inside other expressions.

Every language I've used except BASIC has used True == 1, False == 0,
but I'm sure there are some which use other values. If True == -1,
then you simply subtract the bool from the int instead of adding them.
If it's something else, you arrange the array accordingly.

> * there was never any consistency, people would write any of:
>
>  true = 1; false = 0
>  FALSE = 0; TRUE = not FALSE
>  True = -1; False = not True

Just as long as someone doesn't use:
  true = 1; false = -1
which results in the annoying situation that:
  if x == false:
is different from:
  if x:
But on the plus side, TheDailyWTF.com is never short of publishable material...

Chris Angelico

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Equivalent code to the bool() built-in function candide <candide@free.invalid> - 2011-04-16 22:24 +0200
  Re: Equivalent code to the bool() built-in function Chris Rebert <clp2@rebertia.com> - 2011-04-16 13:58 -0700
    Re: Equivalent code to the bool() built-in function Ben Finney <ben+python@benfinney.id.au> - 2011-04-17 07:38 +1000
      Re: Equivalent code to the bool() built-in function candide <candide@free.invalid> - 2011-04-17 01:51 +0200
        Re: Equivalent code to the bool() built-in function Chris Rebert <clp2@rebertia.com> - 2011-04-16 17:16 -0700
        Re: Equivalent code to the bool() built-in function Ben Finney <ben+python@benfinney.id.au> - 2011-04-17 12:39 +1000
          Re: Equivalent code to the bool() built-in function candide <candide@free.invalid> - 2011-04-17 10:38 +0200
            Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-17 18:46 +1000
              Re: Equivalent code to the bool() built-in function Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-04-18 12:12 +1200
                Re: Equivalent code to the bool() built-in function John Nagle <nagle@animats.com> - 2011-04-18 12:58 -0700
                Re: Equivalent code to the bool() built-in function Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-04-19 12:18 +1200
                Re: Equivalent code to the bool() built-in function Christian Heimes <lists@cheimes.de> - 2011-04-19 03:39 +0200
                Re: Equivalent code to the bool() built-in function Kushal Kumaran <kushal.kumaran+python@gmail.com> - 2011-04-19 11:53 +0530
                Re: Equivalent code to the bool() built-in function Grant Edwards <invalid@invalid.invalid> - 2011-04-19 14:23 +0000
                Re: Equivalent code to the bool() built-in function Jean-Paul Calderone <calderone.jeanpaul@gmail.com> - 2011-04-19 08:43 -0700
                Re: Equivalent code to the bool() built-in function Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-04-20 11:59 +1200
                Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-19 16:26 +1000
                Re: Equivalent code to the bool() built-in function Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-04-19 08:43 +0000
                Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-19 19:00 +1000
                Re: Equivalent code to the bool() built-in function Westley Martínez <anikom15@gmail.com> - 2011-04-19 06:43 -0700
            Re: Equivalent code to the bool() built-in function Ben Finney <ben+python@benfinney.id.au> - 2011-04-17 19:46 +1000
              Re: Equivalent code to the bool() built-in function candide <candide@free.invalid> - 2011-04-18 01:22 +0200
                Re: Equivalent code to the bool() built-in function Ben Finney <ben+python@benfinney.id.au> - 2011-04-18 09:46 +1000
                Re: Equivalent code to the bool() built-in function Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-04-18 12:08 +1200
                Re: Equivalent code to the bool() built-in function Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-04-18 00:22 +0000
                Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-18 10:52 +1000
                Re: Equivalent code to the bool() built-in function Duncan Booth <duncan.booth@invalid.invalid> - 2011-04-18 10:01 +0000
            Re: Equivalent code to the bool() built-in function Daniel Kluev <dan.kluev@gmail.com> - 2011-04-17 21:11 +1100
      Re: Equivalent code to the bool() built-in function Daniel Kluev <dan.kluev@gmail.com> - 2011-04-18 10:45 +1100
        Re: Equivalent code to the bool() built-in function Ben Finney <ben+python@benfinney.id.au> - 2011-04-18 10:36 +1000
      Re: Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-18 11:52 +1000
      Re: Re: Equivalent code to the bool() built-in function Dave Angel <davea@ieee.org> - 2011-04-17 21:46 -0400
      Re: Re: Equivalent code to the bool() built-in function Daniel Kluev <dan.kluev@gmail.com> - 2011-04-18 14:16 +1100
      Re: Equivalent code to the bool() built-in function Ned Deily <nad@acm.org> - 2011-04-17 21:40 -0700
      Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-18 14:53 +1000
        Re: Equivalent code to the bool() built-in function Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-04-19 12:22 +1200
      Re: Equivalent code to the bool() built-in function Chris Rebert <clp2@rebertia.com> - 2011-04-17 22:49 -0700
        Re: Equivalent code to the bool() built-in function Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-04-18 06:14 +0000
      Re: Equivalent code to the bool() built-in function Chris Angelico <rosuav@gmail.com> - 2011-04-18 16:03 +1000
  Re: Equivalent code to the bool() built-in function Ben Finney <ben+python@benfinney.id.au> - 2011-04-17 07:13 +1000
    Re: Equivalent code to the bool() built-in function candide <candide@free.invalid> - 2011-04-17 01:51 +0200
  Re: Equivalent code to the bool() built-in function Raymond Hettinger <python@rcn.com> - 2011-04-18 01:33 -0700
    Re: Equivalent code to the bool() built-in function candide <candide@free.invalid> - 2011-04-18 11:19 +0200

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