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Groups > comp.lang.python > #39489

Re: Python Newbie

References <cad0eacc-6040-4a00-bd05-7fabfd2fa70e@googlegroups.com> <5c262e95-b3a8-4f2a-b752-84b30bf4f81e@googlegroups.com>
From Oscar Benjamin <oscar.j.benjamin@gmail.com>
Date 2013-02-21 23:27 +0000
Subject Re: Python Newbie
Newsgroups comp.lang.python
Message-ID <mailman.2214.1361489278.2939.python-list@python.org> (permalink)

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On 21 February 2013 22:40,  <piterrr.dolinski@gmail.com> wrote:
> Thanks to all for quick relies.
>
> Chris, you are (almost) spot on with the if blocks indentation. This is what I do, and it has served me well for 15 years.
>
> code
> code
>
>    if (some condition)
>    {
>       code
>       code
>    }
>
> code
> code

So you already indent blocks in an "if" construct? This is good
practise in some languages and is enforced in Python. Once I got used
to it I found that the compulsory whitespace made it easier to read
conditional code blocks.

>
> This is what I call code clarity. With Python, I am having to do this
>
> code
> code
>
> ##############################
>
> if (some condition):
>   code
>   code
>
> ##############################
>
> code
> code
>
> It does the job, but is not ideal.

Do you mean that you literally insert a line of '#' characters before
and after in "if" block? There's no need to do that. Just allow
yourself to acclimatise to the significant whitespace and you'll find
that it's easy to see where the block begins and ends.

>
> I am nervous about using variables "out of the blue", without having to declare them. For example, when I write "i = 0" it is perfectly OK to Python without 'i' being declared earlier. How do I know that I haven't used this variable earlier and I am unintentionally overwriting the value? I find I constantly have to use the search facility in the editor, which is not fun.
>
> You see, Javascript, for one, behaves the same way as Python (no variable declaration) but JS has curly braces and you know the variable you have just used is limited in scope to the code within the { }. With Python, you have to search the whole file.

No, you only have to search the whole function which for me is rarely
more than 20 lines. The statement "i=0" when inside a function will
not overwrite anything outside the function (unless you use the
global/nonlocal statements). I rarely use global variables or module
level variables and if I do then I usually have a special place in a
module/script for defining them. I also tend to name them in ALLCAPS
just like C-preprocessor macros that need to be carefully maintained
in a separate "namespace".

>
> Thanks to Chris, Ian and Dave for explaining the () issue around if and for statement. I don't agree with this, but I understand your points. The reason why I like parentheses is because they help with code clarity. I am obsessed with this. :-) After all, there is a reason why so many languages have required them for several decades.

You'll get used to using the colon in the same way.

>
> What about Python's ambiguity?
> For example, in C you would write
>
> if (myVar != 0)
>   do something
>
> in Python, this is legal
>
> if (not myVar):
>   do something
>
> What does this mean? Is it a test for myVar being equal to zero or a test for null, or else?

All of those things. It executes "do something" if myVar is
1) zero (whether int/float/complex etc.)
2) False
3) None
4) an empty collection (list/set/tuple etc.)
5) an empty string
6) and more...

If the context doesn't make it clear what you are testing for then use
a more specific test (myVar!=0 works just as well).

> I want to learn a new language but Python's quirks are a bit of a shock to me at this point. I have been Pythoning only for about a week.
>
> In the mean time, thanks to most of you for encouraging me to give Python a chance. I will do my best to like it, w/o prejudice.

Many of the things that have confused/concerned you are things that I
actually like about Python. Given time you may do as well.


Oscar

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Thread

Python Newbie Piterrr <piterrr.dolinski@gmail.com> - 2013-02-21 13:26 -0800
  Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-21 14:54 -0700
  Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-21 21:58 +0000
  Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 08:59 +1100
  Re: Python Newbie Peter Pearson <ppearson@nowhere.invalid> - 2013-02-21 22:03 +0000
  Re: Python Newbie Dave Angel <davea@davea.name> - 2013-02-21 17:22 -0500
  Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-21 14:40 -0800
    Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 10:21 +1100
      Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-21 15:34 -0800
        Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-21 23:48 +0000
        Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 11:32 +1100
        Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 11:58 -0700
      Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-21 15:34 -0800
    Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-21 23:27 +0000
    Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-21 16:55 -0700
    Re: Python Newbie rusi <rustompmody@gmail.com> - 2013-02-21 22:57 -0800
    Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-22 10:26 +0000
      Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-22 12:05 +0100
      Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 22:23 +1100
    Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 16:04 -0700
    Re: Python Newbie Vito De Tullio <vito.detullio@gmail.com> - 2013-02-24 09:23 +0100
    Re: Python Newbie "J.R." <groups_jr-1@yahoo.com.br> - 2013-02-24 23:02 -0300
      Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 21:03 -0500
        Re: Python Newbie "J.R." <groups_jr-1@yahoo.com.br> - 2013-02-24 23:35 -0300
        Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 13:31 +1100
  Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-21 19:35 -0500
  Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-21 23:50 -0500
    Re: Python Newbie Rui Maciel <rui.maciel@gmail.com> - 2013-02-22 11:58 +0000
      Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-22 23:12 +1100
        Re: Python Newbie Rui Maciel <rui.maciel@gmail.com> - 2013-02-22 13:50 +0000
          Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 01:05 +1100
            Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-23 00:03 +0000
              Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 11:21 +1100
          Re: Python Newbie Duncan Booth <duncan.booth@invalid.invalid> - 2013-02-22 14:26 +0000
            Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-22 15:45 +0100
              Re: Python Newbie Duncan Booth <duncan.booth@invalid.invalid> - 2013-02-22 15:02 +0000
            Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 02:06 +1100
              Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 13:37 -0800
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-22 22:08 +0000
                Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-22 15:45 -0700
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 15:38 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 11:17 +1100
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-23 13:29 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 08:38 +1100
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 15:52 -0700
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 10:18 +1100
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-23 15:46 -0800
                Re: Python Newbie Larry Hudson <orgnut@yahoo.com> - 2013-02-23 20:20 -0800
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 14:34 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 07:46 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 02:52 +1100
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 11:22 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-24 17:44 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 11:29 -0800
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 21:35 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 14:43 -0800
                Re: Python Newbie Joel Goldstick <joel.goldstick@gmail.com> - 2013-02-24 18:05 -0500
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 23:13 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 14:43 -0800
                Re: Python Newbie Larry Hudson <orgnut@yahoo.com> - 2013-02-26 00:32 -0800
                Re: Python Newbie rurpy@yahoo.com - 2013-02-26 10:23 -0800
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-26 10:59 -0800
                Re: Python Newbie rurpy@yahoo.com - 2013-02-26 13:30 -0800
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 18:31 -0700
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 09:08 +1100
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-24 23:18 +0000
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 22:51 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 15:38 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 10:45 +1100
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 15:53 -0800
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 16:08 -0800
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-25 00:28 +0000
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-25 00:38 +0000
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 16:33 -0800
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-25 00:45 +0000
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 19:50 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 01:04 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 12:27 +1100
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 18:42 -0700
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 12:24 +1100
                Re: Python Newbie Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-25 01:44 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 12:53 +1100
                Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-25 02:23 +0000
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 18:59 -0800
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 16:08 -0800
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 19:42 -0500
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 15:38 -0800
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 23:21 +0000
                Re: Python Newbie Dave Angel <davea@davea.name> - 2013-02-24 17:47 -0500
                Re: Python Newbie Serhiy Storchaka <storchaka@gmail.com> - 2013-02-25 14:40 +0200
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 07:46 -0800
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 22:23 -0700
                Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-24 00:11 +0000
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 12:37 -0500
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 10:56 -0700
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 13:07 -0500
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 21:01 -0500
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 15:38 -0800
                Re: Python Newbie Terry Reedy <tjreedy@udel.edu> - 2013-02-22 20:04 -0500
                Re: Python Newbie rurpy@yahoo.com - 2013-02-22 18:48 -0800
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-22 20:47 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-23 02:02 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 13:18 +1100
                Re: Python Newbie Grant Edwards <invalid@invalid.invalid> - 2013-02-24 18:19 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:25 +1100
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-22 21:40 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-23 13:48 +1100
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-23 02:59 +0000
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-23 13:34 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 08:40 +1100
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 12:41 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-23 04:13 +0000
                Re: Python Newbie Serhiy Storchaka <storchaka@gmail.com> - 2013-02-23 11:48 +0200
                Re: Python Newbie Rui Maciel <rui.maciel@gmail.com> - 2013-02-23 12:30 +0000
                Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-23 16:43 +0100
                Re: Python Newbie jmfauth <wxjmfauth@gmail.com> - 2013-02-23 10:44 -0800
                Re: Python Newbie Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-23 12:13 -0700
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-23 11:08 -0800
                Re: Python Newbie jmfauth <wxjmfauth@gmail.com> - 2013-02-23 12:53 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 08:48 +1100
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 00:02 +0000
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 12:16 -0700
                Re: Python Newbie Matej Cepl <mcepl@redhat.com> - 2013-02-24 00:06 +0100
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-24 02:51 +1100
                Re: Python Newbie Matej Cepl <mcepl@redhat.com> - 2013-02-24 00:04 +0100
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-23 08:32 -0800
                Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-23 18:39 +0100
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 12:19 -0700
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 17:11 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 11:40 -0800
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-24 15:06 -0500
                Re: Python Newbie "Michael Ross" <gmx@ross.cx> - 2013-02-24 21:33 +0100
                Re: Python Newbie MRAB <python@mrabarnett.plus.com> - 2013-02-24 20:34 +0000
                Re: Python Newbie Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-24 20:41 +0000
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 12:34 -0800
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:42 +1100
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 15:48 -0500
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-24 21:58 +0000
                Re: Python Newbie Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-24 21:08 -0500
                Re: Python Newbie Joshua Landau <joshua.landau.ws@gmail.com> - 2013-02-25 02:59 +0000
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:47 +1100
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 07:58 +1100
                Re: Python Newbie Roy Smith <roy@panix.com> - 2013-02-24 16:08 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 08:44 +1100
                Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-24 17:40 -0500
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 01:11 +0000
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 00:42 +0000
                Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-24 18:34 -0700
                Re: Python Newbie Ethan Furman <ethan@stoneleaf.us> - 2013-02-24 14:33 -0800
                Re: Python Newbie Albert Hopkins <marduk@letterboxes.org> - 2013-02-24 18:32 -0500
                Re: Python Newbie Chris Angelico <rosuav@gmail.com> - 2013-02-25 10:44 +1100
                Re: Python Newbie Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-25 01:06 +0000
                Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-24 11:40 -0800
              Re: Python Newbie piterrr.dolinski@gmail.com - 2013-02-22 13:37 -0800
      Re: Python Newbie Mitya Sirenef <msirenef@lightbird.net> - 2013-02-22 20:05 -0500
  Re: Python Newbie Gene Heskett <gheskett@wdtv.com> - 2013-02-23 12:32 -0500
  Re: Python Newbie Steve Simmons <square.steve@gmail.com> - 2013-02-23 19:10 +0100
  Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 11:40 -0700
  Re: Python Newbie Michael Torrie <torriem@gmail.com> - 2013-02-23 12:15 -0700
  Re: Python Newbie Gene Heskett <gheskett@wdtv.com> - 2013-02-23 17:49 -0500
  Re: Python Newbie Nick Mellor <thebalancepro@gmail.com> - 2013-02-25 19:37 -0800

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