Python 相对导入导致 SyntaxError 异常 [英] Python relative import causes SyntaxError exception

问题描述

根据 python 文档，相对导入和包内从 python 2.5 开始支持引用.我目前正在运行 Python 2.7.3.因此，我尝试在我自己的包中实现它，以便将其用于更简单的导入.我很惊讶地发现它向我抛出了一个 SyntaxError 异常，我希望有人能帮助找到原因.

According to the python docs, relative importing and intrapackage referencing has been supported since python 2.5. I am currently running Python 2.7.3. So, I tried to implement this in my own package in order to use it for simpler importing. I was surprised to find it threw a SyntaxError exception at me, and I was hoping someone could help lead the way to the cause.

我设置了一个测试目录进行测试:

I setup a test directory for testing:

tester
├── __init__.py
├── first_level.py
└── sub
    ├── __init__.py
    └── second_level.py

两个 __init__.py 模块都是空的.其他模块是:

Both __init__.py modules are empty. The other modules are:

# first_level.py
print "This is the first level of the package"

<小时>

# sub/second_level.py
import ..first_level
print "This is the second level"

<小时>

当我尝试导入 second_level 模块时，出现以下错误:

---

When I attempt to import the second_level module, I get the following error:

Python 2.7.3 (default, Aug  1 2012, 14:42:42) 
[GCC 4.2.1 Compatible Apple Clang 4.0 ((tags/Apple/clang-421.0.57))] on darwin
Type "help", "copyright", "credits" or "license" for more information.
Welcome!
>>> import tester
>>> import tester.sub.second_level
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "tester/sub/second_level.py", line 1
    import ..first_level
           ^
SyntaxError: invalid syntax

我希望这两行一个接一个地打印，但它引发了一个异常.那么，我做的导入错了吗?你还有其它的想法吗.

I expected the two lines to print one after the other, but it raises an exception instead. So, am I doing the import wrong? Do you have any other ideas.

推荐答案

你不能像那样导入模块.import ..blah 不是有效的导入语法.你需要做 from .. import first_level.

You can't import modules like that. import ..blah is not valid import syntax. You need to do from .. import first_level.

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