模块安装，但不能导入。

Question

我对Python很陌生，我试图在Mac上运行一个依赖于模块的Python2脚本，我已经安装了这个模块，但是根据脚本无法找到。为什么下面的失败？

Home:Dev m$ python -V
Python 2.7.10
Home:Dev m$ sudo pip install coincurve==5.2.0 pysha3
Password:
The directory '/Users/m/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/Users/m/Library/Caches/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Collecting coincurve==5.2.0
  Downloading coincurve-5.2.0-cp27-cp27m-macosx_10_6_intel.whl (157kB)
    100% |████████████████████████████████| 163kB 1.3MB/s 
Collecting pysha3
  Downloading pysha3-1.0.2.tar.gz (829kB)
    100% |████████████████████████████████| 829kB 692kB/s 
Requirement already satisfied: cffi>=1.3.0 in /usr/local/lib/python2.7/site-packages (from coincurve==5.2.0)
Requirement already satisfied: asn1crypto in /usr/local/lib/python2.7/site-packages (from coincurve==5.2.0)
Requirement already satisfied: pycparser in /usr/local/lib/python2.7/site-packages (from cffi>=1.3.0->coincurve==5.2.0)
Installing collected packages: coincurve, pysha3
  Running setup.py install for pysha3 ... done
Successfully installed coincurve-5.2.0 pysha3-1.0.2
Home:Dev m$ pip show coincurve
Name: coincurve
Version: 5.2.0
Summary: Cross-platform Python CFFI bindings for libsecp256k1
Home-page: https://github.com/ofek/coincurve
Author: Ofek Lev
Author-email: ofekmeister@gmail.com
License: MIT/Apache-2.0
Location: /usr/local/lib/python2.7/site-packages
Requires: cffi, asn1crypto
Home:Dev m$ python
Python 2.7.10 (default, Jul 15 2017, 17:16:57) 
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import coincurve
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named coincurve
>>> 

Answer 1

问题是，实际上您并不在python2.7shell中。在某些Linux发行版中，您必须指定python版本才能进入其shell。因此，运行以下命令：

python2

而不是：

python

因为上面的命令会自动打开python3.xshell。