如何使用 `venv` 更新 Python 虚拟环境以使用较新版本的 Python？

Question

我最近安装了 Python 3.8.0 和 Python 3.7.4。

我有一些虚拟环境（使用python -m venv <directory>基于 v3.7.4创建的环境。如何更新它们以使用 v3.8.0？

我是否需要创建一个新的虚拟环境并重新安装依赖项、脚本等？

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注意：有一些现有的问答（例如这个）处理旧的virtualenv包/工具。我特别询问新的内置venv模块，它是自 v3.3 以来 Python 的标准内置模块，并且与virtualenv.

Answer 1

我猜你要找的是--upgrade参数。

python -m venv --help
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.

您需要使用目标 python 版本运行它，例如在这种情况下：

python3.8 -m venv --upgrade <path_to_dir>

假设 python3.8 是你的 python 3.8.0 可执行文件的名称。