为此我喜欢使用穷人的解决方案:只需删除 ~/.emacs.d/elpa/(或在您的 package-directory-list 中指定的目录).

I like to use the poor's man solution for that: just remove the directory for the unwanted package in ~/.emacs.d/elpa/ (or the directory specified in your package-directory-list).

此解决方案适用于出现问题的场景(可能是错误，可能是手动修改包数据的结果).请使用@lunaryon 回答；在 99.9% 的情况下，这是正确的做法.

this solution is intended for scenarios where something went wrong (maybe a bug, maybe the result of manual tinkering with packages' data). Please use @lunaryon answer; it is the right way of doing this on the 99.9% of the cases.