即使模块已安装，也会发生ImportError

Question

I'm installing packages on virtual env.

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

But if I install it using pip , it says:

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

Answer 1

我认为您应该在虚拟环境中尝试pip install constants

(venv)$ pip install constants