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注意 sys.path 最左边的值，除了空字符串...

从根目录，python -c "import sys; print(sys.path)"给我：

['', '/home/brian/code/indep/chimai', '/home/brian/code/indep/google_search/src', '/usr/lib/python33.zip', 
'/usr/lib/python3.3', '/usr/lib/python3.3/plat-linux', '/usr/lib/python3.3/lib-dynload', '/usr/lib/python3.3/site-packages']

从我的主目录：

['', '/home/brian/home/brian/code/indep/chimai', '/home/brian/code/indep/google_search/src', 
'/usr/lib/python33.zip', '/usr/lib/python3.3', '/usr/lib/python3.3/plat-linux', '/usr/lib/python3.3/lib-dynload', 
'/usr/lib/python3.3/site-packages']

从 /boot/grub：

['', '/boot/grub/home/brian/code/indep/chimai', '/home/brian/code/indep/google_search/src', '/usr/lib/python33.zip', 
/usr/lib/python3.3', '/usr/lib/python3.3/plat-linux', '/usr/lib/python3.3/lib-dynload', '/usr/lib/python3.3/site-packages']

无论我从哪个目录进行测试，这种行为都会继续。也就是说，您看到的 sys.path 的第二个和第三个值应该从我的 PYTHONPATH 变量中加载，但第一个值总是将我的当前目录附加到它的前面。

此外，python -Sc "import sys; print(sys.path)由于某种原因，不这样做。使用该命令，我总是得到：

['', 'home/brian/code/indep/chimai', '/home/brian/code/indep/google_search/src', '/usr/lib/python33.zip', 
'/usr/lib/python3.3/', '/usr/lib/python3.3/plat-linux', '/usr/lib/python3.3/lib-dynload']

这一切都非常令人惊讶。site.py 对此负责吗？有人可以指出我正确的方向吗？我只是想导入我自己的模块，目前由于某种原因无法导入。

4

1 回答 1

0

从 site.py 的文档字符串：

"""Append module search paths for third-party packages to sys.path.

****************************************************************
* This module is automatically imported during initialization. *
****************************************************************

In earlier versions of Python (up to 1.5a3), scripts or modules that
needed to use site-specific modules would place ``import site''
somewhere near the top of their code.  Because of the automatic
import, this is no longer necessary (but code that does it still
works).

This will append site-specific paths to the module search path.  On
Unix (including Mac OSX), it starts with sys.prefix and
sys.exec_prefix (if different) and appends
lib/python<version>/site-packages as well as lib/site-python.
On other platforms (such as Windows), it tries each of the
prefixes directly, as well as with lib/site-packages appended.  The
resulting directories, if they exist, are appended to sys.path, and
also inspected for path configuration files.

A path configuration file is a file whose name has the form
<package>.pth; its contents are additional directories (one per line)
to be added to sys.path.  Non-existing directories (or
non-directories) are never added to sys.path; no directory is added to
sys.path more than once.  Blank lines and lines beginning with
'#' are skipped. Lines starting with 'import' are executed.

For example, suppose sys.prefix and sys.exec_prefix are set to
/usr/local and there is a directory /usr/local/lib/python2.5/site-packages
with three subdirectories, foo, bar and spam, and two path
configuration files, foo.pth and bar.pth.  Assume foo.pth contains the
following:

  # foo package configuration
  foo
  bar
  bletch

and bar.pth contains:

  # bar package configuration
  bar

Then the following directories are added to sys.path, in this order:

  /usr/local/lib/python2.5/site-packages/bar
  /usr/local/lib/python2.5/site-packages/foo

Note that bletch is omitted because it doesn't exist; bar precedes foo
because bar.pth comes alphabetically before foo.pth; and spam is
omitted because it is not mentioned in either path configuration file.

After these path manipulations, an attempt is made to import a module
named sitecustomize, which can perform arbitrary additional
site-specific customizations.  If this import fails with an
ImportError exception, it is silently ignored.

"""

至于导入您自己的模块，以下规则适用：

如果模块在您当前的工作目录中，则可以使用简单的方式导入它，如果import mymodule 它在当前工作目录的子目录中，您可以将其导入，就subdir.mymodule好像您在当前工作目录的子目录中有一个模块包和包包含一个名为的文件，该文件__init__.py声明了一个名为的列表， __all__ = ['modulename', 'another', 'etc']然后您可以使用from subdir import modulename or import subdir和使用subdir.etc.fn()等。

如果您的模块是您需要在多个地方使用但不是在所有地方使用的模块，您可以将其放在一个公共位置，然后在需要时将该位置附加/插入到 sys.path 中。如果它是您几乎一直都需要的东西，那么您可以通过将它放在适当的位置并添加一个 .pth 文件来将它添加到您的站点包中。最后，如果您认为其他人会从您的软件包中受益，您可以使用 distutils 将其捆绑起来并将其添加到奶酪店之类的地方或以其他方式分发。

于 2013-07-25T05:57:49.460 回答