即使模块已安装，也会出现ImportError

Question

我正在虚拟环境中安装软件包。

(venv)pynanomsg]$ python 
    >>> import constants 
    Traceback (most recent call last): 
     File "<stdin>", line 1, in <module> 
    ImportError: No module named constants 

但如果我安装它使用pip，它说：

$ pip install constants 
Requirement already satisfied: constants in  /usr/local/lib/python2.7/site-packages 

Answer 1

我想你应该在你的虚拟环境中尝试pip install constants

(venv)$ pip install constants