python - 如何降级conda版本？

Question

我需要在我的 CentOS 6.7 机器上将我的 conda 版本从 4.3 降级到 4.2。执行此操作所需的命令是什么？

Answer 1

我不建议降级 conda，除非新安装(升级)的版本存在严重错误。

但是既然你问了:你可以通过将 ={version} 附加到包来指定一个版本，这甚至适用于 conda 包:

$ conda install conda=4.2

如果您想要特定的 4.2 版本，您还可以使用(例如):

$ conda install conda=4.2.15

请注意，降级 conda 可能非常危险。降级后，您的 conda 可能会完全失败或无法正常工作。 Conda 使用大量随时间演变的元数据......因此，如果降级的 conda 版本无法理解这些 - 或者更糟的是破坏它们 - 你将在如何恢复你的 conda 环境方面经历痛苦的​​经历。 降级 conda 风险自负(在我看来，只有在真的，真的有必要时才这样做)!

---

如果您已经降级 conda 并且它向您抛出异常(例如 CondaUpgradeError)，那么可能是 troubleshooting guide in the conda repository 中的这个“部分”可能有用:

Conda upgrade error

Cause

Downgrading conda from 4.6.1 to 4.5.x and then trying to conda install conda or conda upgrade conda will produce a solving and upgrade error similar to the following:

Solving environment: failed
CondaUpgradeError: This environment has previously been operated on by a
conda version that's newer than the conda currently being used. A newer
version of conda is required.
target environment location: /opt/conda
current conda version: 4.5.9
minimum conda version: 4.6

Solution

Change the .condarc file. Set the parameter by editing the .condarc file directly: allow_conda_downgrades: true in conda version 4.5.12. This will then let you upgrade. If you have something older than 4.5.12, install conda 4.6.1 again from the package cache.

EXAMPLE: If my conda info says package cache : /opt/conda/pkgs and my Python version is 3.7, then on the command line, type conda install /opt/conda/pkgs/conda-4.6.1-py37_0.tar.bz2 to resolve the issue.