--- tags: Python title: Python virtual environment(虛擬環境) --- # Python 虛擬環境架設 [參考連結](https://docs.python.org/zh-tw/3/tutorial/venv.html) ## 1. 通過 `venv` 來創造一個虛擬環境: ```console python -m venv <YOUR-PATH> ``` `venv` 參數介紹: ```console usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear] [--upgrade] [--without-pip] [--prompt PROMPT] ENV_DIR [ENV_DIR ...] Creates virtual Python environments in one or more target directories. positional arguments: ENV_DIR A directory to create the environment in. optional arguments: -h, --help show this help message and exit --system-site-packages Give the virtual environment access to the system site-packages dir. --symlinks Try to use symlinks rather than copies, when symlinks are not the default for the platform. --copies Try to use copies rather than symlinks, even when symlinks are the default for the platform. --clear Delete the contents of the environment directory if it already exists, before environment creation. --upgrade Upgrade the environment directory to use this version of Python, assuming Python has been upgraded in-place. --without-pip Skips installing or upgrading pip in the virtual environment (pip is bootstrapped by default) --prompt PROMPT Provides an alternative prompt prefix for this environment. Once an environment has been created, you may wish to activate it, e.g. by sourcing an activate script in its bin directory. ``` ## 2. 進入/離開虛擬環境 進入虛擬環境: ```console source <YOUR-PATH>/bin/activate ``` 離開虛擬環境: ```console deactivate ``` ## 3. 安裝所需 packages 可先寫好 `requirements.txt`，直接打: ```console pip install -r requirements.txt ``` `requirements.txt` 寫法: ``` --find-links https://download.pytorch.org/whl/torch_stable.html matplotlib numpy torch==1.10.0+cu113 torchvision==0.11.1+cu113 torchaudio===0.10.0+cu113 torchsummary ``` ## 4. 刪除虛擬環境 直接刪除資料夾即可: ```console rm <YOUR-VENV> -rf ``` ## P.S. 輸出當前的 `pip packages` 到 `requirements.txt` ```console pip freeze > requirements.txt ```