所以我重新安装了 MacPorts Python。我有port select --set python python27并which python返回正确的位置，即/opt/local/bin。现在，当我在 Python 解释器中导入模块时，我相信首先在非 MacPorts 目录中查找模块，即/Library/Python/2.7/site-packages/。
我相信这是因为这些输出print(sys.path)：
['',
'/Library/Python/2.7/site-packages/nose-1.1.2-py2.7.egg',
'/Library/Python/2.7/site-packages/DateUtils-0.5.1-py2.7.egg',
'/Library/Python/2.7/site-packages/ipython-0.13.dev-py2.7.egg',
'/Library/Python/2.7/site-packages/matplotlib-1.2.x-py2.7-macosx-10.7-intel.egg',
'/Library/Python/2.7/site-packages/numpy-1.7.0.dev_3cb783e_20120427-py2.7-macosx-10.7-x86_64.egg',
'/Library/Python/2.7/site-packages/pandas-0.7.3_20120507-py2.7-macosx-10.7-x86_64.egg',
'/Library/Python/2.7/site-packages/pymc-2.2beta-py2.7-macosx-10.7-intel.egg',
'/Library/Python/2.7/site-packages/scipy-0.10.1_20120427-py2.7-macosx-10.7-x86_64.egg',
'/Library/Python/2.7/site-packages/statsmodels-0.4.0-py2.7-macosx-10.7-intel.egg',
'/Library/Python/2.7/site-packages/readline-6.2.2-py2.7-macosx-10.7-intel.egg',
'/Library/Python/2.7/site-packages/pip-1.1-py2.7.egg',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python27.zip',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages',
'/Library/Python/2.7/site-packages',
'/Library/Python/2.7/site-packages/PIL']
我的问题是：所有这些都是/Library/Python/2.7/site-packages/.....etc.必要的吗？或者我可以删除它们，这样 Python 只会浏览/opt/目录吗？然后，如果找不到它，它会查找最后添加的这两个条目：/Library/Python...寻找其他包？