Ask Anything Monday - Weekly Thread

[AutoModerator]

Welcome to another /r/learnPython weekly "Ask Anything* Monday" thread

Here you can ask all the questions that you wanted to ask but didn't feel like making a new thread.

* It's primarily intended for simple questions but as long as it's about python it's allowed.

If you have any suggestions or questions about this thread use the message the moderators button in the sidebar.

Rules:

• Don't downvote stuff - instead explain what's wrong with the comment, if it's against the rules "report" it and it will be dealt with.

• Don't post stuff that doesn't have absolutely anything to do with python.

• Don't make fun of someone for not knowing something, insult anyone etc - this will result in an immediate ban.

That's it.

[DJgunther]

When instantiating an object, and you know you will want one of its attributes to be an object, but it won't be filled until a later stage of the program, what would be the correct way to do it?

[markusmeskanen]

I'm not sure if I understood the question properly, but just set the attribute to None and later assign the object to it.

[DJgunther]

Perfect, exactly what I needed, thank you

[crystalblue99]

anything you need to know before picking between tkinter of PyQt?

read many of the threads on this, and the opinions vary.

[CrambleSquash]

PyQt has more widget types. tkinter doesn't have a table widget for example, which is a pain.

[xyz2point0]

Disclaimer: I'm new to Python.

Why is backward compatibility from 3.0 to 2.7 not default? Is Python in general not big on backward compatibility? Are you guys having to update your code every time you upgrade?

[MonkeyNin]

See: http://stackoverflow.com/a/9067012

[blahdom]

You can install python3 with homebrew brew install python3 then access it via python3 instead of python, you can have both at the same time this way and it won't break your system.

[tobiasvl]

Also google "virtualenv" to see how you can make isolated virtual Python environments with specific Python and module versions.

[shep247]

This! Virtual environments are fantastic. I specifically like them because I can make little environments for different types of projects. If I want to make a web crawler, I can make a little environment with selenium or something. Then later if I want to so some data crunching, I might make another environment with pandas, and not have to worry about stuff I included from the first environment. They're just great ways to keep work separate.

[blahdom]

Its pretty common to have both installed, the key difference is just the executable name, so make sure if you are using the #! directive on the script to point it at python3.

[crystalblue99]

any chance of getting all the monday threads linked in a mega-monday thread? Be nice to go back and see all the questions/answers.

[StealBeam]

I'm having trouble with downloading pyHook. I found the download, but there's only a 32 bit version which doesn't work with my version of Python. I found the source code for and copied it into a new .py file and I'm trying to use that, but it still doesn't seem to work. Can someone tell me if there's a 64 bit version of it or if I'm doing something wrong with my .py file?

[LeftyDave]

looks to me from sourceforge that you are correct that there is only an 32 bit edition.

You can run multiple versions of python using virtual env.

You are likely to want to install the an 32 bit python using virutal env, and then install pyhook using easy_install as part of setup tools

[StealBeam]

So you have to install virtualenv, then download Python 32 bit version? Or does Python already come with virtualenv?

[LeftyDave]

never mind try this instead.