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

问题描述

根据 python docs ，相对导入和内包装自python 2.5以来一直支持引用。我目前正在运行Python 2.7.3。所以，我试图在我自己的包中实现它，以便更简单地导入它。我很惊讶地发现它向我抛出了一个SyntaxError异常，我希望有人可以帮助引领这个原因。

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

__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"

---

---

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

---

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

我预计这两行会一个接一个地打印，但它会引发异常。那么，我做错了导入吗？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

您无法导入类似的模块。 import ..blah 无效的导入语法。你需要从.. import first_level 做。

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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