Python3 Environment Setup and Installation Guide

This section introduces how to set up a local Python 3 development environment.

Python 3 runs on many platforms such as Windows, Linux, and macOS.

Python3 Download

The latest source code, binaries, and documentation can be found on the official Python website: https://www.python.org/ . Documentation is available in HTML, PDF, and PostScript formats at https://www.python.org/doc/ .

Python Installation

Python has been ported to many platforms. You need to download the appropriate binary for your platform or compile from source if a binary is unavailable.

Compiling from source offers more flexibility.

Unix & Linux Platform Installation

Simple steps to install Python on Unix/Linux:

Open a web browser and visit https://www.python.org/downloads/source/ .

Select the source archive for Unix/Linux.

Download and extract the archive, e.g., # tar -zxvf Python-3.6.1.tgz

Configure, build, and install: # cd Python-3.6.1 # ./configure # make && make install

Verify the installation: # python3 -V

Windows Platform Installation

Download the executable installer from https://www.python.org/downloads/windows/ . Choose the appropriate 32‑bit (x86) or 64‑bit (x86‑64) version.

During installation, check “Add Python 3.6 to PATH”. After installation, open the command prompt (Win+R, type cmd ) and run python to verify.

macOS Platform Installation

macOS includes Python 2.7 by default. Download the latest Python 3.x installer from https://www.python.org/downloads/mac-osx/ or build from source.

Environment Variable Configuration

Programs and executables may reside in directories not included in the system’s search path. The PATH variable stores these directories.

On Unix/Linux, add Python to PATH using:

<code>export PATH="$PATH:/usr/local/bin/python"</code>

On Windows, add Python to PATH via the command prompt:

<code>path=%path%;C:\Python</code>

Alternatively, modify the system’s Path variable through the Control Panel → System → Advanced system settings → Environment Variables.

Python Environment Variables

Variable

Description

PYTHONPATH

Search path for Python modules.

PYTHONSTARTUP

File executed on interpreter startup.

PYTHONCASEOK

Make module imports case‑insensitive.

PYTHONHOME

Alternative module search path.

Running Python

Three ways to run Python:

Interactive Interpreter

Start the interpreter from the command line:

<code>$ python   # Unix/Linux</code>

<code>C:\>python   # Windows</code>

Command‑Line Scripts

Execute a script file:

<code>$ python script.py   # Unix/Linux</code>

<code>C:\>python script.py   # Windows</code>

Ensure the script has execute permissions.

IDE (e.g., PyCharm)

PyCharm is a popular Python IDE supporting macOS, Windows, and Linux. Download it from https://www.jetbrains.com/pycharm/download/ .