Setting up an editor for programming

Python comes with its IDLE, and you can use it in this tutorial. If you don't like using it for some reason, you need PowerShell, command prompt or terminal for trying out things. You also need an editor for writing code that will be stored in files.

If you use IDLE as your editor, it comes with everything set up for you, and you don't need to worry about setting up anything. If you don't, you probably need to change some settings to make your editor suitable for Python use.

Do not use word processors like Microsoft Word and LibreOffice Write for programming. They create their own files, but you need plain text files for programming.

Start by creating an empty file called hello.py and opening it with your editor. Or just open your editor and save a file as hello.py.

Automatic tab expanding

This is important. Never use tabs in Python. Nobody else is using tabs, and the official style guide tells you to never use tabs.

However, you don't need to press the spacebar four times every time you want to indent. Your editor should give you four spaces when you hit the tab key. Some editors also remove four spaces when you hit backspace and there are four spaces before the cursor.

Geany

Go to Edit at the top and select Preferences.
Go to Editor at left.
Go to Indenting at top.
Select Spaces instead of Tabs.

gedit and pluma

Go to Edit at the top and select Preferences.
Go to Editor at top.
Change the indent width to 4 and select Add spaces instead of tabs.

GNU Emacs

Emacs uses spaces with Python files by default.

Mousepad

Go to Document at the top, then Tab Size.
Select 4.
Also select Insert Spaces.

Syntax highlighting

If you type a keyword, like if, it should show up with a different color than the rest of your text. "Strings", # comments and everything else should also have their own colors. This makes it much easier to write code.

Most of the editors below have syntax highlighting turned on by default, but you can also change the colors.

Geany

Install more color schemes, then go to View, Change Color Scheme.

gedit and pluma

Click Fonts & Colors in the preferences and select another color theme.

GNU Emacs

Type M-x, type load-theme, press Tab twice to see a list of theme names, then enter a theme name and press Enter. If you want to automatically set the theme when Emacs starts, add (load-theme 'your-theme-name) to your ~/.emacs.

Mousepad

Click View, go to Color Scheme and select whatever you want.

Is your editor using Python 3?

Some editors allow you to run your programs with a single keystroke, usually by pressing F5. This tutorial is written for Python 3 or newer, so your editor also needs to run the programs in Python 3 or newer.

If you are unsure which Python your editor runs, create a test file with the following contents:

import sys
print(sys.version)

If the version starts with 2, it's too old.

Geany

Go to Build, then Set Build Commands.
Replace python or python2 with python3 everywhere. Or if you are using Windows, run python on a terminal and enter these commands:
```
>>> import sys
>>> print(sys.executable)
```
You'll get a path to your python.exe. Replace python in the build commands with this path. Most importantly, your Execute command should be "C:\your\path" "%f".

gedit, pluma and Mousepad

These editors don't support running programs with F5.

GNU Emacs

Usually I write something in Emacs, then I press Ctrl+Z to suspend Emacs, run the program myself and then I run fg to get back to Emacs. If you know how to run Python programs in Emacs and you'd like to write about it here, tell me.

You may use this tutorial freely at your own risk. See LICENSE.

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