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Re: Implicit conversion to boolean in if and while statements

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On Sun, Feb 10, 2013 at 3:26 PM, Rick Johnson
<rantingrickjohnson@gmail.com> wrote:
> On Friday, February 8, 2013 11:01:00 PM UTC-6, Chris Angelico wrote:
>> [...]
>> Another advantage of using two characters: There's no conflict between
>> set and dict literals. How do you notate an empty set in Python? {}
>> means an empty dict.
>
> What makes you believe that a language must provide literal syntax for EACH and EVERY type? And BTW, if you don't already know, this is how you notate an empty set in Python:
>
> py> set([])
> set([])

Or omit the argument, to avoid working with a pointless empty list.
But what happens if you first execute:

set = tuple

? This is not a set literal, it's an expression that usually returns a set.

> IMO "Set Types" should only exists as a concequence of "freezing" an array, and should have NO literal syntax avaiable.

I don't understand. Wouldn't freezing an array (list) result in a
tuple? And, why should there be no literal syntax for them?

Having a convenient literal notation for every basic type is extremely
handy. You can work with integers 1, 2, 3, or floats 1.0, 2.0, 3.0. C
gives you those. In Python, you can work with lists, too, and C
doesn't give you those (you have array *initializer* syntax, but
that's not the same thing). It's perfectly plausible to dereference a
literal:

dow = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"][day%7]

Of course, it's perfectly plausible to do that with a function, too.
You could define something like this:

def agg(*args): return args
dow = agg("Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat")[day%7]

But the question is, why? Why call a function when the interpreter can
do the work directly at compile stage? There's absolutely no value in
forcing things to be done at run-time.

ChrisA

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Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-07 22:16 -0800
  Re: Implicit conversion to boolean in if and while statements Michael Torrie <torriem@gmail.com> - 2013-02-07 23:27 -0700
    Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-07 22:32 -0800
    Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-07 22:32 -0800
  Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-09 02:16 +1100
    Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-08 09:48 -0800
      Re: Implicit conversion to boolean in if and while statements Roy Smith <roy@panix.com> - 2013-02-08 12:58 -0500
      Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-08 11:58 -0800
        Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-09 11:05 +1100
          Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-08 16:49 -0800
            Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-09 12:17 +1100
              Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 20:54 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-10 16:04 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 04:28 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-11 23:50 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 05:28 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-12 00:52 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:24 -0800
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:24 -0800
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 05:28 -0800
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 04:28 -0800
              Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 20:54 -0800
            Re: Implicit conversion to boolean in if and while statements Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-08 18:29 -0700
            Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-09 16:01 +1100
              Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 20:26 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-10 15:50 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 18:09 -0800
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 18:09 -0800
                Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-10 22:37 +1100
                Re: Implicit conversion to boolean in if and while statements Roy Smith <roy@panix.com> - 2013-02-10 09:45 -0500
                Re: Implicit conversion to boolean in if and while statements Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2013-02-10 18:06 +0100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 04:18 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-11 23:40 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 05:13 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-12 00:35 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:00 -0800
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:00 -0800
                Re: Implicit conversion to boolean in if and while statements 88888 Dihedral <dihedral88888@googlemail.com> - 2013-02-11 17:06 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-12 16:55 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-12 09:48 -0800
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-13 08:24 +1100
                Re: Implicit conversion to boolean in if and while statements 88888 Dihedral <dihedral88888@googlemail.com> - 2013-02-12 18:43 -0800
                Re: Implicit conversion to boolean in if and while statements 88888 Dihedral <dihedral88888@googlemail.com> - 2013-02-12 18:43 -0800
                Re: Implicit conversion to boolean in if and while statements Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-15 13:12 -0700
                Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2013-02-16 11:12 +1100
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-12 09:48 -0800
                Re: Implicit conversion to boolean in if and while statements 88888 Dihedral <dihedral88888@googlemail.com> - 2013-02-11 17:06 -0800
                Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 05:13 -0800
                Re: Implicit conversion to boolean in if and while statements Serhiy Storchaka <storchaka@gmail.com> - 2013-02-15 21:09 +0200
              Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 20:26 -0800
          Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-08 16:49 -0800
        Re: Implicit conversion to boolean in if and while statements Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-08 18:06 -0700
          Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 22:25 -0800
          Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 22:25 -0800
      Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-09 14:16 +1100
        Re: Implicit conversion to boolean in if and while statements Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-09 15:36 -0500
      Re: Implicit conversion to boolean in if and while statements Mark Janssen <dreamingforward@gmail.com> - 2013-02-11 21:12 -0800

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