Develop Reference

Python on Windows opens new window

Here's the problem, after installing Python (3.6, 3.7, 3.8) on Microsoft Windows when you invoke it, it opens in a new window.
This question has been raised before, and replies talk about modifying the code to pause the output or keep the program running so it doesn't close the window. I can not modify every python package ever made for windows compatability.
My problem is that this is not how Python works on *nix platforms. Surely there must be a way to get python to execute within a command prompt ?
My immediate issue is that I loose the console output on so many python programs. From Jupyter Notebook to AWS GRC (remote-codecommit).
-=-=-=-=-= ANSWER =-=-=-=-=-
After much frustration, it turns out the problem was related to account privileges.
The behaviour above occurred when a user with elevated rights executed Python.
When I log out and run with another user that is a local admin, it now behaves normally.
I cant tell you the exact difference between elevated rights and local admin, but there is something in the permissioning that effects how Python is run on Windows.

This happened to me when the current directory of the terminal didn't exist (was deleted/renamed after the terminal was started).
Solution: cd to some directory.

Find you python folder and select python.exe and create a shortcut for it.
Example Image
There's probably a better way, but this is a simple workaround.

In Visual Studio Code, how do I load my python code to a read-print-eval loop?

I am teaching a class that uses VScode.
I am used to teaching using IDLE, and it is very nice for the students to be able to call their defined functions and run snippets of code in a python terminal, for debugging purposes.
In VScode, they I have been unable to do the same in a satisfactory way.
Option1: I can select all code, right click and run selection/line on terminal. This works for small snippets, but I cannot do it for the whole file (even after selecting the whole file with ctrl-A). On linux, this works, but on windows, it does not, unfortunately (and my students use windows)
Option2: I can use the debug console. This requires adding a breakpoint in one of the last lines of the file, and does not offer tab completion. It works, but is less convenient than IDLE.
Option 3: I can also add the commands to run to the bottom of the file (which is a least preferred alternative, given that is forgoes the interativity of the read-print-eval loop).
Is there any better solution? Installing a VScode extension would not be a problem.

Visual Code is just a text editor like your traditional notepad. to run and debug any kind program you need to install the particular extension for the programming language.
In your case you are using python so you need to install the extension of it. the best one is the "Python" which is developed by microsoft itself. go to your extensions manager and install this extension. right click and click "run python file in terminal" and you are all set.
this will run exactly as they run from the idle(which is default IDE provided by python itself) you can enter the arguments from the console itself. according to me this is the best way to run and debug python programs in VScode.
another way is that VScode shows which python version is installed on your computer on the left bottom side, click on it and the programs will use this interpreter.
out of all the ways listed here and many others, the best method is to run the program in the terminal which is the recommend by python itself and many other programmers.
this method is very simple. what you have to do is open up your command prompt and type the path where python.exe is installed and the type the path of the your program as the argument and press enter. you are done !
ex : C:\Python27\python.exe C:\Users\Username\Desktop\my_python_script.py
You can also pass your arguments of your program in the command prompt itself.
if you do not want to type all this and then just use the solution mentioned above.
hope that your query is solved.
regards

python or pythonw in creating a cross-platform standalone GUI app

I am developing a simple standalone, graphical application in python. My development has been done on linux but I would like to distribute the application cross-platform.
I have a launcher script which checks a bunch of environment variables and then sets various configuration options, and then calls the application with what amounts to python main.py (specifically os.system('python main.py %s'% (arg1, arg2...)) )
On OS X (without X11), the launcher script crashed with an error like Could not run application, need access to screen. A very quick google search later, the script was working locally by replacing python main.py with pythonw main.py.
My question is, what is the best way to write the launcher script so that it can do the right thing across platforms and not crash? Note that this question is not asking how to determine what platform I am on. The solution "check to see if I am on OS X, and if so invoke pythonw instead" is what I have done for now, but it seems like a somewhat hacky fix because it depends on understanding the details of the windowing system (which could easily break sometime in the future) and I wonder if there is a cleaner way.
This question does not yet have a satisfactory answer.

If you save the file as main.pyw, it should run the script without opening up a new cmd/terminal.
Then you can run it as python main.pyw

Firstly, you should always use .pyw for GUIs.
Secondly, you could convert it to .exe if you want people without python to be able to use your program. The process is simple. The hardest part is downloading one of these:
for python 2.x: p2exe
for python 3.x: cx_Freeze
You can simply google instructions on how to use them if you decide to go down that path.
Also, if you're using messageboxes in your GUI, it won't work. You will have to create windows/toplevels instead.

Easy way to launch Python scripts with the mouse in OS-X

I'd like to write cross platform Python scripts that are GUI frontends for command line programs. The problem is I know a few Mac users who think that using the terminal will have the same effect as throwing their computer off the top of a skyscraper. In Linux and Windows it's easy enough to setup a Python script so the user can double click an icon and the script will start without opening any extra windows. Is there an easy way to do this with OS-X? Would the user have to install a different Python than the one that comes with OS-X? I haven't been able to find a definitive answer.

You might want to look at Platypus. It's a freeware app for generating apps which wrap scripts.
Another way to do something like that is using Automator or even AppleScript Editor. Either can produce an application which just runs a script.
Update:
For Automator: Launch Automator, select the Application template, type "script" in the search field, double-click Run Shell Script, switch the shell pop-up menu to /usr/bin/python, type/paste your Python script into the text field. Or, leave the pop-menu on /bin/bash and just write an invocation of an external script in the text field. Save as an application.
You can also view help from its Help menu.
For AppleScript, launch AppleScript Editor, type the following as the script:
do shell script "/usr/bin/true"
Replace /usr/bin/true with the path to whatever script you like. Save as an application.
Again, there's help in the Help menu.

py2app does this with aplomb. You make your Python script, use whatever dependencies you need (wx, Tkinter, etc.) and py2app makes you a standalone app bundle that will run in any modern OS X environment. It bundles Python too, so you can use any Python you want (not just the system default).
The downside is that the generated apps might be large, up to 50MB if you have a lot of dependencies (though that is somewhat of an extreme).

There are two ways to do this:
Click on a script.
Press command-i to open the "get info" window.
Expand the "Open With" section (if it isn't already).
Choose "Python Launcher" from the drop-down menu.
Click "Change All" if you would like ALL Python scripts to launch when double clicked.
Possibly open Python Launcher and uncheck "Run in a Terminal window"
This will work for this machine only, so it is less portable than the following. Why? Because the default for opening a document type varies depending on what is installed (XCode and/or IDLE will both take over opening a .py file).
Method Two:
Validate the Interpreter Directive, that's the first line of the file. I suggest using /usr/bin/env python3. This will run the first python3 interpreter that is on the users path.
Make the script executable chmod a+x <script_name> from the Terminal.
Change the extension from .py to .command (this will be opened by the Terminal).
Use zip or tar for distribution so that the permissions do not get mangled.
This method will open a Terminal window, but when the Python window is closed the terminal window will also close.
If your script has dependencies outside of the standard library, then you should provide a second .command file to install those. This may make things more complicated, but using pip3 install --user <list of dependencies> should minimize complications.

Python IDE on Linux Console

This may sound strange, but I need a better way to build python scripts than opening a file with nano/vi, change something, quit the editor, and type in python script.py, over and over again.
I need to build the script on a webserver without any gui. Any ideas how can I improve my workflow?

put this line in your .vimrc file:
:map <F2> :w\|!python %<CR>
now hitting <F2> will save and run your python script

You should give the screen utility a look. While it's not an IDE it is some kind of window manager on the terminal -- i.e. you can have multiple windows and switch between them, which makes especially tasks like this much easier.

You can execute shell commands from within vim.

Using emacs with python-mode you can execute the script with C-c C-c

you can try ipython. using its edit command, it will bring up your editor (nano/vim/etc), you write your script, and then on exiting you're returned to the ipython prompt and the script is automatically executed.

When working with Vim on the console, I have found that using "tabs" in Vim, instead of having multiple Vim instances suspended in the background, makes handling multiple files in Vim more efficient. It takes a bit of getting used to, but it works really well.

You could run XVNC over ssh, which is actually passably responsive for doing this sort of thing and gets you a windowing GUI. I've done this quite effectively over really asthmatic Jetstart DSL services in New Zealand (128K up/ 128K down =8^P) and it's certainly responsive enough for gvim and xterm windows. Another option would be screen, which lets you have multiple textual sessions open and switch between them.

There are actually 2 questions. First is polling for a console IDE for python and the second is a better dev/test/deploy workflow.
For while there are many ways you can write python code in the console, I find a combination of screen, vim and python/ipython is the best as they are usually available on most servers. If you are doing long sessions, I find emacs + python-mode typically involves less typing.
For a better workflow, I would suggest setting up a development environment. You can easily setup a Linux VM on your desktop/laptop easily these days - there isn't a excuse not to even if it's for hobby projects. That opens up a much larger selection of IDEs available to you, such as:
GUI versions of VI and friends
Remote file editing with tramp and testing locally with python-mode inside Emacs
http://www.netbeans.org
and of course http://eclipse.org with the PyDev plugin
I would also setup a SCM to keep track of changes so that you do
better QA and use it to deploy tested changes onto the server.
For example I use Mercurial for my pet projects and I simply tag my repo when it's ready and update the production server to the tag when I deploy. On the devbox, I do:
(hack hack hack, test test test)
hg ci -m 'comment'
hg tag
hg push
Then I jump onto the server and do the following when I deploy:
hg update
restart service/webserver as needed

Well, apart from using one of the more capable console editors (Emacs or vi would come to mind), why do you have to edit it on the web server itself? Just edit it remotely if constant FTP/WebDAV transfer would seem to cumbersome.
Emacs has Tramp Mode, gedit on Linux and bbedit on the Mac support remote editing, too. Probably quite a large number of other editors. In that case you would just edit in on a more capable desktop and restart the script from a shell window.

For what it's worth, VIM alone can do the same tasks as previously posted. I have had the same problem with testing Python from the command line.
My solution was to use the screen command. I split screens vertically, I run Python in one instance of a shell, and on the second screen, I usually edit Python code with VIM.
Command to install screen:
sudo apt-get install screen
The screen package has a bit of a learning curve but there isn't any mystery if you can remember the "Ctrl-Alt ?" command that contains all knowledge.
No GUI is required!