Re: 1 > 0 == True -> False

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Date	Fri, 31 Jan 2014 00:55:44 +1100
Subject	Re: 1 > 0 == True -> False
From	Chris Angelico <rosuav@gmail.com>
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On Fri, Jan 31, 2014 at 12:40 AM, Thibault Langlois
<thibault.langlois@gmail.com> wrote:
> The recommendations to student are 1) do not assume True == 1 and do not use operator chaining.

Not "do not use", but "do not misuse". Python's operator chaining is
awesome for bounds checking:

if 3 < x < 20:
  print("x is between 3 and 20, exclusive")

You can even, since it short-circuits, do crazy stuff like:

x = random.randrange(30)
if int(input("Min: ")) < x < int(input("Max: ")):
    print("It's within those bounds.")

It won't ask for a maximum if it's already failed to be within the
minimum. (Okay, don't do this one. Not good code. Heh.)

But don't use operator chaining when you don't mean it to behave that
way. That's all!

ChrisA

Thread

1 > 0 == True -> False Thibault Langlois <thibault.langlois@gmail.com> - 2014-01-30 03:36 -0800
  Re: 1 > 0 == True -> False Thomas Mlynarczyk <thomas@mlynarczyk-webdesign.de> - 2014-01-30 12:44 +0100
  Re: 1 > 0 == True -> False Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-01-30 13:46 +0200
    Re: 1 > 0 == True -> False Peter Otten <__peter__@web.de> - 2014-01-30 13:04 +0100
      Re: 1 > 0 == True -> False Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-01-30 14:08 +0200
  Re:1 > 0 == True -> False Dave Angel <davea@davea.name> - 2014-01-30 07:49 -0500
    Re: 1 > 0 == True -> False Thibault Langlois <thibault.langlois@gmail.com> - 2014-01-30 05:40 -0800
      Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 00:55 +1100
      Re: 1 > 0 == True -> False Roy Smith <roy@panix.com> - 2014-01-30 09:08 -0500
        Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 01:18 +1100
          Re: 1 > 0 == True -> False Roy Smith <roy@panix.com> - 2014-01-30 09:49 -0500
            Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 02:02 +1100
        Re: 1 > 0 == True -> False Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-01-30 06:41 -0800
        Re: 1 > 0 == True -> False Thibault Langlois <thibault.langlois@gmail.com> - 2014-01-30 06:46 -0800
          Re: 1 > 0 == True -> False Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-30 17:42 +0000
        Re: 1 > 0 == True -> False Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-01-30 16:56 +0200
          Re: 1 > 0 == True -> False Roy Smith <roy@panix.com> - 2014-01-30 10:46 -0800
            Re: 1 > 0 == True -> False Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-01-30 22:14 +0200
              Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 07:25 +1100
        Re: 1 > 0 == True -> False Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-01-30 15:09 +0000
          Re: 1 > 0 == True -> False Rustom Mody <rustompmody@gmail.com> - 2014-01-30 07:34 -0800
          Re: 1 > 0 == True -> False Roy Smith <roy@panix.com> - 2014-01-30 10:53 -0800
            Re: 1 > 0 == True -> False Rustom Mody <rustompmody@gmail.com> - 2014-01-30 19:33 -0800
          Re: 1 > 0 == True -> False Roy Smith <roy@panix.com> - 2014-01-30 10:56 -0800
            Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 06:03 +1100
              Re: 1 > 0 == True -> False Roy Smith <roy@panix.com> - 2014-01-30 14:09 -0800
                Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 09:29 +1100
            Re: 1 > 0 == True -> False Ethan Furman <ethan@stoneleaf.us> - 2014-01-30 11:22 -0800
            Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 06:48 +1100
    Re: 1 > 0 == True -> False Rotwang <sg552@hotmail.co.uk> - 2014-01-30 19:25 +0000
      Re: 1 > 0 == True -> False Dave Angel <davea@davea.name> - 2014-01-30 15:08 -0500
      Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 07:15 +1100
      Re: 1 > 0 == True -> False Ian Kelly <ian.g.kelly@gmail.com> - 2014-01-30 13:28 -0700
      Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 07:38 +1100
      Re: 1 > 0 == True -> False Ian Kelly <ian.g.kelly@gmail.com> - 2014-01-30 14:17 -0700
      Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 08:31 +1100
      Re: 1 > 0 == True -> False Joshua Landau <joshua@landau.ws> - 2014-01-30 23:36 +0000
        Re: 1 > 0 == True -> False Rotwang <sg552@hotmail.co.uk> - 2014-01-31 00:10 +0000
          Removal of iterable unpacking in function calls (was: 1 > 0 == True -> False) Ben Finney <ben+python@benfinney.id.au> - 2014-01-31 11:21 +1100
            Re: Removal of iterable unpacking in function calls Rotwang <sg552@hotmail.co.uk> - 2014-01-31 00:32 +0000
          Re: 1 > 0 == True -> False Joshua Landau <joshua@landau.ws> - 2014-01-31 00:32 +0000
      Re: 1 > 0 == True -> False Chris Angelico <rosuav@gmail.com> - 2014-01-31 11:01 +1100

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