Python 安装

1 Introduction to Python

Python is a widely used, general-purpose programming language known for its readability and rich ecosystem. It runs on Windows, macOS, Linux, and just about every server environment you’ll touch.

This guide walks you through installing Python the right way: getting the correct binary, adding it to your PATH, verifying it works, and creating an isolated environment for your projects.

We’ll keep the steps small, concrete, and repeatable—good habits that avoid cryptic errors later.

2 Choose Your Operating System

Python installers differ per OS. For most developers, the official python.org installers are the safest choice, but package managers can simplify updates.

Windows: use python.org installer or Microsoft Store.
macOS: use python.org, Homebrew, or MacPorts.
Linux: use your distro’s package manager (apt, dnf, pacman) or build from source if you need a custom version.

We’ll verify the installation using the terminal, so keep a shell open as you follow along.

3 Install Python on Windows

Download the latest installer from python.org. Run it and check “Add Python to PATH” before clicking Install. That small checkbox saves you from manual PATH tweaks later.

If you prefer a store-based flow, Microsoft’s Store also offers Python 3.x with automatic PATH updates.

Tip: If you already installed without “Add to PATH”, just reinstall and check the box. It’s the quickest fix.

4 Install Python on macOS

Most macOS workflows prefer a package manager to keep tools in sync.

Option A — Homebrew:

brew install python

Option B — python.org:

# After installing, pin the version you want to use
sudo ln -sf /usr/local/opt/python/bin/python3 /usr/local/bin/python

Homebrew handles PATH links automatically; the manual symlink keeps “python” pointing to the version you expect.

5 Install Python on Linux

Use your distro’s package manager. Many systems ship Python 3 already, but you’ll still want the developer headers and pip.

Debian/Ubuntu:

sudo apt update
sudo apt install -y python3 python3-venv python3-pip

Fedora/CentOS/RHEL:

sudo dnf install -y python3 python3-venv python3-pip

Arch Linux:

sudo pacman -S python

6 Verify Python Is Installed

Open a terminal and confirm the version:

python3 --version

On Windows you can also use:

py --version

You should see “Python 3.x.y”. If not, your PATH isn’t pointing to the right binary—see the next step.

7 Ensure pip Is Available

pip is the standard package installer for Python. Confirm it’s installed:

python3 -m pip --version

If pip is missing, you can install it using the official get-pip script:

python3 -m ensurepip --upgrade

8 Manage PATH on Windows

If “python” or “python3” is not recognized, add your Python installation to PATH.

Find your Python install directory (e.g., C:\Users\you\AppData\Local\Programs\Python\Python311\).
Open System Properties → Environment Variables.
Append the install path and its Scripts subdirectory to the “Path” user variable.

Test with a new terminal:

python --version
python -m pip --version

9 Use the py Launcher (Windows)

Windows includes a “py” launcher that can select a specific Python version.

# List installed Python versions
py -0

# Run a script with Python 3.11
py -3.11 script.py

This helps when you have multiple Python versions side-by-side.

10 Create a Virtual Environment

Project-specific environments keep dependencies tidy. Create one with venv:

python3 -m venv .venv

Activate it, then install packages with pip:

# macOS/Linux
source .venv/bin/activate

# Windows (Command Prompt)
.venv\Scripts\activate

# Install a package (example)
python -m pip install --upgrade pip

11 Run Your First Script and Finish

Create a tiny script and run it to confirm everything works:

echo 'print("Hello, Python")' > hello.py
python hello.py

You should see “Hello, Python”. If you did, you now have a working Python setup and a clean environment to build in.

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