Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #84537

Re: Delegation in Python

From Terry Reedy <tjreedy@udel.edu>
Subject Re: Delegation in Python
Date 2015-01-24 20:31 -0500
References <FeCdnXdsTpunvlnJnZ2dnUVZ8judnZ2d@brightview.co.uk>
Newsgroups comp.lang.python
Message-ID <mailman.18120.1422149503.18130.python-list@python.org> (permalink)

Show all headers | View raw

On 1/24/2015 5:57 PM, Brian Gladman wrote:
> I would appreciate advice on how to set up delgation in Python.
>
> I am continuously implementing a function to test whether a Python
> Fraction is an integer

Since Fractions are reduced to lowest terms,
 >>> from fractions import Fraction as F
 >>> F(4, 2)
Fraction(2, 1)
 >>> F(12, 3)
Fraction(4, 1)

the test is that the denominator is 1

 >>> F(12,3).denominator == 1
True
 >>> F(12,5).denominator == 1
False

it may not be worth the bother to define a function,

def fint(F): return F.denominator == 1

>so I wanted to define a new class, based on
> Fraction, that includes this new method.

but if you do, there is little need to make it a method.  You are not 
overriding an existing method or adding a new special method.  The math 
module has float and int functions that have *not* been turned into 
methods.  Ditto for cmath.  I would just leave the function a function. 
  Python is not Java.

-- 
Terry Jan Reedy

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 22:57 +0000
  Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 10:22 +1100
    Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 23:38 +0000
      Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 10:43 +1100
        Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-25 00:18 +0000
          Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 11:28 +1100
            Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-25 07:49 +0000
              Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 19:07 +1100
      Re: Delegation in Python Gary Herron <gherron@digipen.edu> - 2015-01-24 15:47 -0800
        Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 23:58 +0000
  Re: Delegation in Python Gary Herron <gherron@digipen.edu> - 2015-01-24 15:41 -0800
    Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 23:52 +0000
  Re: Delegation in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-01-24 23:59 +0000
  Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 11:07 +1100
  Re: Delegation in Python Terry Reedy <tjreedy@udel.edu> - 2015-01-24 20:31 -0500
    Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-25 07:43 +0000

csiph-web