安装了minizinc，但python认为没有

Question

pip说minizinc已经安装了，但当我尝试在代码中调用它时，它给我一个错误，说它没有安装。

(backend) bash-3.2$ python
Python 3.8.3 (default, Jul  2 2020, 11:26:31) 
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from minizinc import Instance, Model, Solver
/Users/miranda/.local/share/virtualenvs/backend-BjqhdW2P/lib/python3.8/site-packages/minizinc/__init__.py:25: RuntimeWarning: MiniZinc was not found on the system. No default driver could be initialised.
  warnings.warn(
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name 'Instance' from 'minizinc' (/Users/miranda/.local/share/virtualenvs/backend-BjqhdW2P/lib/python3.8/site-packages/minizinc/__init__.py)
>>> exit()
(backend) bash-3.2$ pip install minizinc
Requirement already satisfied: minizinc in /Users/miranda/.local/share/virtualenvs/backend-BjqhdW2P/lib/python3.8/site-packages (0.4.2)
(backend) bash-3.2$ python3 -m pip install minizinc
Requirement already satisfied: minizinc in /Users/miranda/.local/share/virtualenvs/backend-BjqhdW2P/lib/python3.8/site-packages (0.4.2)
(backend) bash-3.2$ python -m pip install minizinc
Requirement already satisfied: minizinc in /Users/miranda/.local/share/virtualenvs/backend-BjqhdW2P/lib/python3.8/site-packages (0.4.2)

Answer 1

正如MiniZinc Python的"Getting Started"页面上所解释的那样。Python与MiniZinc本身并不相同，它只是一个从MiniZinc到MiniZinc的连接。

这意味着在使用Python之前，您还必须安装MiniZinc包。这就是错误试图告诉您的。该捆绑包可以在MiniZinc website上找到。

请注意，安装完成后，每当您使用MiniZinc进行import minizinc操作时，Python都会在您的计算机上查找minizinc可执行文件。如果您没有在通常的位置安装MiniZinc，那么您可能需要在您的PATH环境变量后面附加minizinc所在的目录才能使其工作。