Develop Reference

How can I make .py files run using Python Shell by default?

I made a Python GUI using Tkinter, but when I run it directly (double click the file) it opens the black python window but automatically closes by itself in less than half a second. I found a way to make it open the IDLE editor but it just opens the editor and doesn't run it.
I want it to run the way it runs when you open the IDLE editor and press Run Module. This runs it using Python Shell.
Is there a way I can make it automatically run using Python Shell?

Based on Mark Tolonen's comment you should do two things
rename your file to a .pyw from .py to prefer console-less runs
set your system to open .pyw files with pythonw if that's not configured already
Linux: configure xdg-open
Windows: right click and choose an application from the context menu (you may need to find where Python is installed to select the pythonw.exe executable)

Okay, one of the comments on the original question is correct.
As Terry Jan Reedy (user:722804) said,
It is possible that your mygui.py file is missing 'root.mainloop()' or the equivalent to start the GUI. IDLE lets you omit that during development so that one can interact with tkinter to retrieve values and make changes to widgets.
Adding gui.mainloop() to the end of my program worked.

How to run python script without writing command on cmd again and again

I am practicing python code and executing it through command line. each time i have to execute my python file i go to cmd and write
D:\PythonPractice>python myClass.py
Is there any standard and comfortable way available to execute python code quickly?

If you are executing the same command, with no changes to arguments or anything, you can pack it in a .bat file (windows executable)
Name it something like myscript.bat
D:\PythonPractice>python C:\path\to\myClass.py
Put full path inside it. Now double click will do.

Use PyCharm Software by JetBrains (same company who developed Android studio and Kotlin language), it will help you in many ways .
Run Python with single press of a button.
Add modules easily just with some clicks.
Debugging the code as smooth as possible.
It is Awesome, I am using it for past couple of months.

you can change file association which controls what to do when invoking filename in command line. For instance, when you just type text filename in cmd, notepadd will be opened, for word docs Word or other document editor.
Have a look into following link from google or you can fiddle by yourself starting from Control Panel > Control Panel Home > Default Programs > Set Associations. Select a file type in the list and click Change Program.
Alternatively,you can use any of Python IDE (PyCharm,PyDev etc.) so you will be able to run directly scripts from editor.

With Notepad++, you can also create a shortcut to be able to launch your python script :
Menu Run > Run (or press F5)
Choose the python .exe (default in C:\Program Files (x86)\Python36-32\python.exe
Then add this code next to the path : "$(FULL_CURRENT_PATH)"
This will allow to execute the current file
example of command with Python 3.6 :
"C:\Program Files (x86)\Python36-32\python.exe" "$(FULL_CURRENT_PATH)"
Then save the command, by assigning a shorcut key, it's better with a modifier like SHIFT (SHIFT + F10)
Now you can launch any script with this shortcut.

Wing ide "run" button is greyed out unless I save the file

Whenever I create a new wing file in the wing IDE interface, I find the "run code" (play symbol) button is greyed out and I can't click it unless I save the file somewhere on my computer. It didn't used to to this.
This is annoying because it forces you to save every single code you write even if it's just 5 lines you've written to test something out.
I can't recall exactly when the button changed, I didn't notice it immediately. But I've updated both my wing IDE and python to the latest version. I've also shifted the directory that I keep all my python saves in, but I can't see why that would matter.
I've taken a look through settings, but I couldn't make much sense of it. I'm new to programming.

Wing has never been able to debug an unsaved file. I suspect you used Wing 101 previously and now use Wing Personal or Wing Pro where the toolbar buttons are a bit different and run things in the debugger instead of evaluating in the Python Shell.
You can still evaluate the file or a selection in the file in the Python Shell using the items in the Source menu. As of Wing 6 you can also debug things you execute in this way by enabling debug in the Python Shell's Options menu.
You can also select a range in the file, click on the active range icon in top right of the Python Shell to make it the active range and then use the cog icon that appears in top right of the Python Shell whenever you want to reevaluate the range as you edit it in the editor.

how to output all the lines into python console in vim?

I have set F2 prompt key with map <f2> :w<cr>:! D:\Python34\python %<cr>,when i open an python file in vim and press F2,the python file will be executed .For a simple example,
here is my python file and opened in gvim .
Now i can't input other python lines ,only thing i can do is to see the result and hit any key to close this window.
What i want is :
when i press F2, (the python file was opened in gvim) ,the python console pop up,and all the files in the python file were copied into the python console automatically,and i can go no to input some lines such as Obj().hello in the python console or go on to edit in gvim ,i am a lazy man ,the gvim and python console all opened waiting to serve me , can i write a vim scripts to achieve the target?
The command :!D:\Python34\python -i % works fine ,i got the ouput
There is still a problem remain,
1)when command :!D:\Python34\python -i % works ,the gvim window will be frozen , i can't drag my mouse to see codes in vim.
2)there is no any python codes in the python console wiondow
So if the program is full of many lines ,and i can't remember the previous content ,worse still， the gvim window frozen ,how can i get the codes?

Avoid blocking
To make the call asynchonous (to avoid that GVIM is blocked during the Python session), use the Windows-specific :!start command:
nnoremap <f2> :w<cr>:!start D:\Python34\python -i %<cr>
List teh codez
I don't know whether it is possible to list the passed source code from the interactive Python debugger. But you can print the file contents before starting it:
nnoremap <f2> :w<cr>:!start cmd /c type % && D:\Python34\python -i %<cr>
Additional tips
You should use :noremap; it makes the mapping immune to remapping and recursion.
As your mapping only works correctly from normal mode, use :nnoremap (or extend it to support visual-mode selections, too).

Maybe Vim plugin Conque will solve your problem:
Installation instrucions are here https://code.google.com/p/conque/
To use just type :ConqueTermVSplit python -i test.py (VSplit is for vertical split - you may use horizontal)
There is no blocking of your window with python code - you may escape interactive mode and switch to your window with Ctrl+W twice

You could approach the problem from the Python angle (2.7).
Keep the file where it is (or save it with some unique name to a temporary directory) and have python load the file directly.
Go to that location in your shell and run python interactively (or have vim spin off an interpreter for you)
Import your file import demo
Experiment with what you have implemented demo.SomeModule().meth()
Make some changes in vim
Reload your python module reload(demo)
Experiment with your code again demo.SomeModule().differentMeth()
You can also have vim create a file with shortcut functions for loading/reloading the file you are working on. When vim kicks off the interpreter, you can have it set this file to the PYTHONSTARTUP environment variable, which is a file the interpreter will automatically load when it starts up. For example, you could have a function called r() to automatically reload the file you are working on.
It's also worth mentioning that reloading modules can be a little weird. If you instantiate some modules then reload the file, only new modules will use the new code; the old modules will run with the old code.

Default working directory for Python IDLE?

Is there a configuration file where I can set its default working directory? It currently defaults to my home directory, but I want to set it to another directory when it starts. I know I can do "import os" followed by "os.chdir("")" but that's kind of troublesome. It'd be great if there is a conf file that I can edit and change that setting, but I am unable to find it.
In particular, I've looked into my OS (Ubuntu)'s desktop entry '/usr/share/applications/idle-python3.2.desktop', which doesn't contain a conf file, but points to '/usr/lib/python3.2/idlelib/PyShell.py', which points to config-*.def conf files under the same folder, with 'config-main.def' being the most likely candidate. However I am unable to find where the default path is specified or how it can be changed.
It seems that the path is hard-coded in PyShell.py, though I could be wrong with my limited knowledge on Python. I will keep looking, but would appreciate it if somebody knows the answer on top of his or her head. Thanks in advance.

I actually just discovered the easiest answer, if you use the shortcut link labeled "IDLE (Python GUI)". This is in Windows Vista, so I don't know if it'll work in other OS's.
1) Right-click "Properties".
2) Select "Shortcut" tab.
3) In "Start In", write file path (e.g. "C:\Users...").
This is also my answer here: Default save path for Python IDLE? Let me know if this works!

I've found a solution after looking into PyShell.py:
Create a python file under a preferred directory, in my case '~/.idlerc/init.py', and copy/paste the following lines:
import os
os.chdir('<your preferred directory>')
Pass "-r '~/.idlerc/init.py' " argument to the IDLE startup command, like the following (your exec location and name may vary depending on OS, etc):
/usr/bin/idle-python3.2 -n -r ~/.idlerc/init.py

Just use a shell script such as:
#!/bin/bash
cd /Users/pu/Projects/L-Python
/usr/bin/idle
and run that instead of stock idle. The example is on OS X, adapt to your system.

I'm new to python and learning from 'Dive into Python' by mark Pilgrim (can be found online free)
the answer is in chapter 2.4 - hope he doesn't mind me pasting it here as its also plugging his book and is in the GPL
Before you go any further, I want to briefly mention the library
search path. Python looks in several places when you try to import a
module. Specifically, it looks in all the directories defined in
sys.path. This is just a list, and you can easily view it or modify it
with standard list methods. (You'll learn more about lists later in
this chapter.)
Example 2.4. Import Search Path
import sys
sys.path
sys.path.append('/my/new/path')
It's a good book I am a programmer - usually I find learning from books sends me quickly to sleep - not the case here ....

All I had to do here (Linux Mint 18.2 Xfce) ...
Just add path in line "working directory" = "Arbeitsverzeichnis"

It can change depending on where you installed Python. Open up IDLE, import os, then call os.getcwd() and that should tell you exactly where your IDLE is working on.

One default path is specified in idlelib.IOBinding.IOBinding.dirname or idlelib.IOBinding.IOBinding.filename
Ubuntu
So my idle-python3.desktop
file in /usr/share/applications looks like this:
[Desktop Entry]
Name=IDLE (using Python-3)
Comment=Integrated Development Environment for Python (using Python-3)
Exec=python3 -c "import idlelib.IOBinding, os; idlelib.IOBinding.IOBinding.dirname='/DEFAULT/DIRECTORY';import idlelib.idle"
Icon=/usr/share/pixmaps/python3.xpm
Terminal=false
Type=Application
Categories=Application;Development;
StartupNotify=true
To use it you need to set /DEFAULT/DIRECTORY to your desired directory, copy it with root rights into /usr/share/applications. You can also use it for Python 2 but then you need to replace the 3s with 2s.
ConfigFiles
There are also extensions that can be loaded. These must be modules and you specify them by module name. The config files for IDLE are located in HOME/.idlerc and parsed with a configparser. I did not get further with this.

Here's a way to reset IDLE's default working directory for MacOS if you launch Idle as an application by double-clicking it. You need a different solution if you launch Idle from a command line in Terminal. This solution is a permanent fix. You don't have to rechange the directory everytime you launch IDLE. I wish it were easier.
The idea is to edit a resource file inside of the IDLE package in Applications.
Start by finding the the file. In Finder, go to IDLE in Applications (in the Python folder) as if you wanted to open it. Right click and select "show package contents". Open Contents, then open Resources. In Resources, you'll see a file called idlemain.py. This file executes when you launch idle and sets, among other things, the working directory. We're going to edit that.
But before you can edit it, you need to give yourself permission to write to it. To do that, right click on the idlemain.py and select get info. Scroll to the bottom of the getinfo window and you'll see the Sharing & Permissions section. On the bottom right there's a lock icom. Click the lock and follow the prompts to unlock it. Once it's unlocked, look to the left for the + (under the list of users with permissions). Click it. That will bring up a window with a list of users you can add. Select yourself (probably the name of your computer or your user account) and click Select. You'll see yourself added to the list of names with permissions. Click where is says "Read only" next to your name and change it to "Read & Write". Be careful not to change anything else. When you're done, click the lock again to lock the changes.
Now go back to idlemain.py and open it with any text editor (you could use Idle, TextEdit, or anything. Right under the import statement at the top is the code to change the default working directory. Read the comment if you like, then replace the single line of code under the comment with
os.chdir('path of your desired working directory')
Mine looks like this:
os.chdir('/Users/MyName/Documents/Python')
Save your changes (which should work because you gave yourself permission). Next time you start Idle, you should be in your desired working directory. You can check with the following commands:
import os
os.getcwd()

This ought to be the number one answer. I have been playing around this for an hour or more and nothing worked. Paul explains this perfectly. It's just like the PATH statement in Windows. I successfully imported a module by appending my personal "PythonModules" path/dir on my Mac (starting at "/users/etc") using a simple
import xxxx command in Idle.