pythonvirtualenv拾取错误的库

我使用Python3创建了一个新的virtualenv，但无法访问全局站点包

$ virtualenv --version
13.0.3

然后我使用virtualenv的Python3解释器，尝试导入

pygments

$ virtualenv --no-site-packages venv_pygments --python=/usr/local/bin/python3
Running virtualenv with interpreter /usr/local/bin/python3
Using base prefix '/usr/local/Cellar/python3/3.4.3/Frameworks/Python.framework/Versions/3.4'
New python executable in venv_pygments/bin/python3.4
Also creating executable in venv_pygments/bin/python
Installing setuptools, pip, wheel...done.

所以看起来virtualenv的Python3正在访问全局站点包。我怎样才能避免呢

当我为virtualenv安装pygments时，它不会改变

$ bin/pip freeze
wheel==0.24.0

$bin/pip安装pygments
收集pygments
使用缓存的Pygments-2.0.2-py3-none-any.whl
安装收集的软件包：pygments
已成功安装pygments-2.0.2
$venv_pygments bin/python3
Python 3.4.3（默认值，2015年5月1日，19:14:18）
[GCC 4.2.1达尔文兼容苹果LLVM 6.1.0（clang-602.0.49）]
有关详细信息，请键入“帮助”、“版权”、“信用证”或“许可证”。
>>>导入pygments
回溯（最近一次呼叫最后一次）：
文件“”，第1行，在
文件“/Applications/QGIS.app/Contents/Resources/python/pygments/_uinit__;u.py”，第46行
除了TypeError，err:
^
SyntaxError:无效语法
>>> 

---

---

注意：原始问题已根据注释进行了更新。

创建隔离环境而不访问全局站点包。有意启用/禁用该行为。默认情况下，最新版本禁用访问

我假设您需要一个隔离的环境来测试Python 3.3.4。 下面我使用的是系统python 2.7.6提供的virtualenv

$ bin/pip install pygments
Collecting pygments
  Using cached Pygments-2.0.2-py3-none-any.whl
Installing collected packages: pygments
Successfully installed pygments-2.0.2
$ venv_pygments  bin/python3
Python 3.4.3 (default, May  1 2015, 19:14:18) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.49)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pygments
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Applications/QGIS.app/Contents/Resources/python/pygments/__init__.py", line 46
    except TypeError, err:
                    ^
SyntaxError: invalid syntax
>>> 

我创建了一个virtualenv，切换到目录中，并使用相对路径从这个virtualenv中寻址python解释器和pip

$ virtualenv --version
1.11.2

$ virtualenv
You must provide a DEST_DIR
Usage: virtualenv [OPTIONS] DEST_DIR

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -v, --verbose         Increase verbosity.
  -q, --quiet           Decrease verbosity.
  -p PYTHON_EXE, --python=PYTHON_EXE
                        The Python interpreter to use, e.g.,
                        --python=python2.5 will use the python2.5 interpreter
                        to create the new environment.  The default is the
                        interpreter that virtualenv was installed with
                        (/usr/bin/python)
  --clear               Clear out the non-root install and start from scratch.
  --no-site-packages    DEPRECATED. Retained only for backward compatibility.
                        Not having access to global site-packages is now the
                        default behavior.
  --system-site-packages
                        Give the virtual environment access to the global
                        site-packages.
  --always-copy         Always copy files rather than symlinking.
  --unzip-setuptools    Unzip Setuptools when installing it.
  --relocatable         Make an EXISTING virtualenv environment relocatable.
                        This fixes up scripts and makes all .pth files
                        relative.
  --no-setuptools       Do not install setuptools (or pip) in the new
                        virtualenv.
  --no-pip              Do not install pip in the new virtualenv.
  --extra-search-dir=DIR
                        Directory to look for setuptools/pip distributions in.
                        This option can be used multiple times.
  --never-download      DEPRECATED. Retained only for backward compatibility.
                        This option has no effect. Virtualenv never downloads
                        pip or setuptools.
  --prompt=PROMPT       Provides an alternative prompt prefix for this
                        environment.
  --setuptools          DEPRECATED. Retained only for backward compatibility.
                        This option has no effect.
  --distribute          DEPRECATED. Retained only for backward compatibility.
                        This option has no effect.

在创建virtualenv时，您需要继续使用该选项

--python=/usr/local/bin/python3

如您所做的那样引用Python3.3.4解释器

最近的默认virtualenv通常只安装了几个软件包。如果你有更多，你可以访问全球网站包

$ virtualenv --no-site-packages venv_pygments
New python executable in venv_pygments/bin/python
Installing setuptools, pip...done.
$ cd venv_pygments/
$ bin/pip install pygments
Downloading/unpacking pygments
  Downloading Pygments-2.0.2-py2-none-any.whl (672kB): 672kB downloaded
Installing collected packages: pygments
Successfully installed pygments
Cleaning up...
$ bin/python
Python 2.7.6 (default, Jun 22 2015, 17:58:13) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pygments
>>> pygments.__version__
'2.0.2'

---

尝试对pip和python使用相对或绝对路径。可能您实际使用的是系统python资源。您是否尝试过使用

pip安装升级pip——升级pip

，就像输出消息中所说的那样？@miindlek是这样做的。没有区别？@saschagotfried您能举个例子说明我如何使用具有相对/绝对路径的pip吗？现在我很确定，您的问题与访问全局站点包有关。查找mkvirtualenv的相关选项以限制对全局站点包的访问。按照您的步骤，我在为python3创建virtualenv时仍然会遇到相同的错误。在创建了一个新的virtualenv之后，pip freeze没有给我预期的站点包。请更新您的问题以反映您所做的事情。请在安装pygments之前尝试导入它。这应该引起两个不同的例外。第一个应该指出缺少一个包，因为您还没有安装它。或者调查virtualenv中的文件和文件夹（站点包），以查找pygments资源或*.pth文件

$ virtualenv --no-site-packages venv_pygments
New python executable in venv_pygments/bin/python
Installing setuptools, pip...done.
$ cd venv_pygments/
$ bin/pip install pygments
Downloading/unpacking pygments
  Downloading Pygments-2.0.2-py2-none-any.whl (672kB): 672kB downloaded
Installing collected packages: pygments
Successfully installed pygments
Cleaning up...
$ bin/python
Python 2.7.6 (default, Jun 22 2015, 17:58:13) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pygments
>>> pygments.__version__
'2.0.2'

$ bin/pip freeze
Pygments==2.0.2
argparse==1.2.1
wsgiref==0.1.2