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Re: When I need classes?

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On 01/10/2016 12:29 AM, Arshpreet Singh wrote:
> Hello Friends, I am quite new to OOP(object oriented Programming), I
> did some projects with python which includes Data-Analysis, Flask Web
> Development and some simple scripts.
> 
> I have only one question which is bothering me most of the time, When
> I will get the need to use Classes in Python? Or in other way is
> there any real-life example where you can tell me this
> problem/solution is kind of impossible in Python without Classes?

I can't speak to Flask or any other web development.  But for simple
scripts, I'll start out with no classes.  Just functions as needed, and
some main logic.  I always use the idiom:

if __name__ == '__main__':
    # do main logic here

This way I can import functions defined in this script into another
script later if I want.

If I find I need to share state between functions, and if I find that I
might need to have multiple situations of shared state possibly at the
same time, then I will refactor the script into a class.  Despite the
apparent shame of using global variables, if I need to share state
between functions, but I cannot ever foresee a time when I'll need to
have multiple instances of that state, then I'll just use a module-level
global variable and continue to use normal functions, rather than define
a class.  In the parlance of OOP, this use case would be referred to as
a "singleton" and a python module (a script) is a form of singleton
already, even without using classes.

In the end my code often is a mix of classes and non-class -based code.

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When I need classes? Arshpreet Singh <arsh840@gmail.com> - 2016-01-09 23:29 -0800
  Re: When I need classes? Michael Torrie <torriem@gmail.com> - 2016-01-10 08:02 -0700
    Re: When I need classes? Arshpreet Singh <arsh840@gmail.com> - 2016-01-10 22:45 -0800
      Re: When I need classes? Cameron Simpson <cs@zip.com.au> - 2016-01-11 18:27 +1100
  Re: When I need classes? Steven D'Aprano <steve@pearwood.info> - 2016-01-11 02:39 +1100
    Re: When I need classes? Bernardo Sulzbach <mafagafogigante@gmail.com> - 2016-01-10 15:48 -0200
      Re: When I need classes? Arshpreet Singh <arsh840@gmail.com> - 2016-01-10 22:24 -0800
    Re: When I need classes? Arshpreet Singh <arsh840@gmail.com> - 2016-01-10 22:28 -0800
    Re: When I need classes? Travis Griggs <travisgriggs@gmail.com> - 2016-01-11 15:45 -0800
      Re: When I need classes? Mike S <mscir@yahoo.com> - 2016-01-13 22:27 -0800
    Re: When I need classes? Michael Torrie <torriem@gmail.com> - 2016-01-11 16:59 -0700
    Re: When I need classes? Bernardo Sulzbach <mafagafogigante@gmail.com> - 2016-01-11 22:53 -0200
    Re: When I need classes? Chris Angelico <rosuav@gmail.com> - 2016-01-12 12:28 +1100
      Re: When I need classes? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-01-13 10:01 +1300
        Re: When I need classes? Bernardo Sulzbach <mafagafogigante@gmail.com> - 2016-01-12 19:08 -0200
    Re: When I need classes? Ian Kelly <ian.g.kelly@gmail.com> - 2016-01-12 17:18 -0700
      Re: When I need classes? Steven D'Aprano <steve@pearwood.info> - 2016-01-13 12:33 +1100
  Re: When I need classes? Rustom Mody <rustompmody@gmail.com> - 2016-01-12 19:36 -0800
    Re: When I need classes? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-01-13 16:27 +1100
      Re: When I need classes? Rustom Mody <rustompmody@gmail.com> - 2016-01-12 22:31 -0800
        Re: When I need classes? Rustom Mody <rustompmody@gmail.com> - 2016-01-13 08:33 -0800
      Re: When I need classes? Rick Johnson <rantingrickjohnson@gmail.com> - 2016-01-14 10:00 -0800

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