Re: [Tutor] When to use classes

On 19/08/17 08:52, Alan Gauld via Tutor wrote: Following up my own post - a sure sign of failure to communicate :-( > On 19/08/17 05:26, boB Stepp wrote: > >> related methods needs to share the same values and a class would tidy >> this up nicely without the need for any globals > Indeed, but

Re: [Tutor] When to use classes

On 19/08/17 05:26, boB Stepp wrote: > related methods needs to share the same values and a class would tidy > this up nicely without the need for any globals or needless passing of > the exact same values around as parameters/arguments. Indeed, but its important to remember that class attributes

Re: [Tutor] When to use classes

Steven D'Aprano wrote: > Mostly for Bob, but also for anyone else interested: > > When To Use Classes > > http://kentsjohnson.com/stories/00014.html Just a minor nit, but you don't even need a custom function for the callback result = [] db.query(sql, result.append) The lesson is that Python

Re: [Tutor] When to use classes

On Sat, Aug 19, 2017 at 4:04 AM, Peter Otten <__pete...@web.de> wrote: > Steven D'Aprano wrote: > >> Mostly for Bob, but also for anyone else interested: >> >> When To Use Classes >> >> http://kentsjohnson.com/stories/00014.html > > Just a minor nit, but you don't even need a custom function for

Re: [Tutor] When to use classes

On Sat, Aug 19, 2017 at 3:07 AM, Alan Gauld via Tutor wrote: > On 19/08/17 08:52, Alan Gauld via Tutor wrote: > > Following up my own post - a sure sign of failure to communicate :-( > >> On 19/08/17 05:26, boB Stepp wrote: >> >>> related methods needs to share the same values

Re: [Tutor] When to use classes

On 19/08/17 10:04, Peter Otten wrote: > nicer interface. Nobody would want to write > > a + b * c > > as > > add(a, mul(b, c)) Unless they program in Lisp perhaps :-) -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow

Re: [Tutor] help with subprocess module

On 08/19/2017 04:13 AM, kay Cee wrote: > I made a python script that will update a Ubuntu Server every second and > writes asuccess message and date to a log file, but for some reason the > file is not being written to. > > Here is the Script: > > #!/usr/bin/python3 > > import subprocess >

Re: [Tutor] When to use classes

On 19Aug2017 11:00, boB Stepp wrote: On Sat, Aug 19, 2017 at 4:04 AM, Peter Otten <__pete...@web.de> wrote: [...] The lesson is that Python already provides some powerful ready-to-use classes that take you a long way without having to write your own custom classes.

Re: [Tutor] When to use classes

On Sat, Aug 19, 2017 at 11:00:51AM -0500, boB Stepp wrote: > I try to keep this in mind. Another thing I'm currently struggling > with is when to use inheritance vs. separate, independent classes. Raymond Hettinger has a good video presentation about the use of classes and inheritance for

Re: [Tutor] help with subprocess module

On 19Aug2017 06:13, kay Cee wrote: update_log = open('update_log.txt', 'r+') Normally one would use 'a' (append) for a log open. I don't see what 'r+' accomplishes for you. In particular I expect it would always write at the start of the log file, overwriting

Re: [Tutor] When to use classes

On Sat, Aug 19, 2017 at 10:52:45AM -0500, boB Stepp wrote: > This thought had occurred to me. Sometimes I wish there was a > mechanism in Python to create a binding to data where both were > unchangeable/immutable. Yes, I could use an immutable data type, but > if I bind an identifier to it

Re: [Tutor] When to use classes

On Sat, Aug 19, 2017 at 11:34:10AM -0600, Mats Wichmann wrote: > It makes some sense though; computational code just goes ahead and > computes. In the graphical UI world, interesting things happen when an > event you can't exactly plan for takes place. From the point of view of > a computer

Re: [Tutor] When to use classes

On 08/19/2017 10:00 AM, boB Stepp wrote: >> (That was easy; but I wonder what tkinter would look like without >> callbacks...) > > I wish I knew more so that I could fully wonder about this myself. > You might even be making a clever joke and I am clueless. All graphics frameworks depend

Re: [Tutor] help with subprocess module

On 19/08/17 11:13, kay Cee wrote: > import subprocess > import time > import datetime > > class UpdateError(Exception): > pass In defining your own type of Exception you implicitly say that you will be raising it somewhere. But you never raise this exception in your code... > def update():

[Tutor] help with subprocess module

I made a python script that will update a Ubuntu Server every second and writes asuccess message and date to a log file, but for some reason the file is not being written to. Here is the Script: #!/usr/bin/python3 import subprocess import time import datetime class

Re: [Tutor] When to use classes

On 19/08/17 17:00, boB Stepp wrote: > I try to keep this in mind. Another thing I'm currently struggling > with is when to use inheritance vs. separate, independent classes. The golden rule is if the child is not a kind-of the parent then it should be delegation not inheritance. Never use

Re: [Tutor] help with subprocess module

kay Cee wrote: > I made a python script that will update a Ubuntu Server every second and > writes asuccess message and date to a log file, but for some reason the > file is not being written to. > > Here is the Script: > > > #!/usr/bin/python3 > > > > import subprocess > > import time >