4 
(myvirtualenv)[~] sam@iota $ type ipython  
ipython is hashed (/usr/local/bin/ipython)  
(myvirtualenv)[~] sam@iota $ which ipython  
/Users/sam/.virtualenvs/myvirtualenv/bin/ipython

不管怎么说which，它执行/usr/local/bin/ipython

(myvirtualenv)[~] sam@iota $ ipython  

WARNING: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.  
Python 2.7.5 (default, Sep  6 2013, 17:51:18)  

IPython 1.1.0 -- An enhanced Interactive Python.

In [1]:  import novaclient
---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-1-93e5b70cb5b9> in <module>()
----> 1 import novaclient

/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/novaclient/__init__.py in <module>()
     16
     17
---> 18 __version__ = pbr.version.VersionInfo('python-novaclient').version_string()

/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/pbr/version.pyc in version_string(self)
     70         if self.version is None:
     71             parts = []
---> 72             for part in self.release_string().split('.'):
     73                 if part[0].isdigit():
     74                     parts.append(part)

/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/pbr/version.pyc in release_string(self)
     62         
     63         if self.release is None:
---> 64             self.release = self._get_version_from_pkg_resources()
     65
     66         return self.release

/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/pbr/version.pyc in _get_version_from_pkg_resources(self)
     55             # installed into anything. Revert to setup-time logic.
     56             from pbr import packaging
---> 57             return packaging.get_version(self.package)
     58
     59     def release_string(self):

/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/pbr/packaging.pyc in get_version(package_name, pre_version)
    820     if version:
    821         return version
--> 822     raise Exception("Versioning for this project requires either an sdist"
    823                     " tarball, or access to an upstream git repository."
    824                     " Are you sure that git is installed?")

Exception: Versioning for this project requires either an sdist tarball, or access to an upstream git repository. Are you sure that git is installed?

现在强制它执行/Users/sam/.virtualenvs/myvirtualenv/bin/ipython

(myvirtualenv)[~] sam@iota $ `which ipython`

Python 2.7.5
Type "copyright", "credits" or "license" for more information.

IPython 1.1.0 -- An enhanced Interactive Python.

In [1]: import novaclient
In [2]: print "all is well here"
all is well here

(myvirtualenv)[~] sam@iota $ echo $PATH
 /Users/sam/.virtualenvs/myvirtualenv/bin:/usr/local/sbin:/usr/local/lib:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin
(myvirtualenv)[~] sam@iota $ python

Python 2.7.5 (default, Sep  6 2013, 17:51:18)
[GCC 4.2.1 Compatible Apple LLVM 4.2 (clang-425.0.24)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import novaclient
>>> print "all is well here"
all is well here
>>> exit()

为什么which和type指向不同的路径？为什么，如果 IPython 安装在我的 virtualenv 中，系统 IPython 会被执行，即使我的顺序$PATH会指示不是这样？无论如何，为什么会import novaclient出现看似非常奇怪的错误？

编辑

来自错误会话的pythonpath

(myvirtualenv)[~] sam@iota $ ipython -c 'import sys;sys.path'

['/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages',
 '',
 '/usr/local/bin',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/setuptools-1.1-py2.7.egg',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-1.4.1-py2.7.egg',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python27.zip',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload',
 '/Library/Python/2.7/site-packages',
 '/usr/local/lib/python2.7/site-packages',
 '/usr/local/lib/python2.7/site-packages/IPython/extensions']

来自成功会话的 pythonpath

(myvirtualenv)[~] sam@iota $ python -c 'import sys;print sys.path'

['',
 '/Users/sam/.virtualenvs/projectx-dev-2/bin',
 '/Users/sam/.virtualenvs/projectx-dev-2/src/pyrax',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python27.zip',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7/plat-darwin',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7/plat-mac',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7/plat-mac/lib-scriptpackages',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7/lib-tk',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7/lib-old',
 '/Users/sam/.virtualenvs/projectx-dev-2/lib/python2.7/lib-dynload',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac',
 '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages',
 '/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages',
 '/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/IPython/extensions']
4

1 回答 1

4

为什么 which 和 type 指向不同的路径？

如果你的 shell 有 hashedipython的路径，type会给你 hashed path而不用 search $PATH，同时which会忽略 hashed path 并进行搜索。

假设您的 shell 是bash，该hash命令（没有参数）将向您显示散列路径，或者您可以查看BASH_CMDS关联数组。但是您已经知道这ipython是散列的，因为type刚刚告诉您。

通常你可以通过启动一个新的shell来解决这个问题，使用hash -r命令（擦除缓存而不重新启动其他任何东西），或者hash -d ipython（只ipython从缓存中删除——但确保你没有，例如，python在缓存中） ）。使用不同的 shell，这两个命令可能不同（例如，在 *csh 和 zsh 中，分别是 it'srehash和rehash ipython），但是启动一个新的 shell 应该总是有效的。

有关更多详细信息，请参阅bash 参考手册中的命令搜索和执行bash(1)，或系统上的联机帮助页，或者如果您在 Google 上搜索“bash 哈希缓存”之类的内容（如一）。

为什么，如果 IPython 安装在我的 virtualenv 中，系统 IPython 会被执行吗

如果你的 shell 有 hashedipython的路径，ipython将从 hashed 路径运行，而不搜索$PATH。

同样，启动一个新的 shell 等应该可以解决这个问题。

无论如何，为什么 import novaclient 会出现看起来很奇怪的错误？

很可能它是PYTHONPATH从您的环境中获取的，这导致 venv 的站点包和 dist 包成为系统 Python 的，并且这些位置的包不适用于系统 Python。

您可以通过打印来验证这一点sys.path。但是它抱怨文件 in 的事实/Users/sam/.virtualenvs/myvirtualenv/lib/python2.7/site-packages/意味着该路径必须是 on sys.path。并且（因为您是从不同的目录运行）不仅因为默认设置.正在获取它，而且因为它明确存在。因此，所有sys.path可以告诉您的是它是绝对路径还是相对路径。

于 2013-11-14T19:00:24.637 回答