Question

当我在配置脚本中导入模块时，我遇到了这种行为，我用它来驱动alembic。该脚本是由我的virtualenv中安装的模块从文件系统动态加载的，这似乎是发生此问题的唯一情况。

以下是堆栈跟踪：

Traceback (most recent call last):
  File "/mnt/home/dmonego/test/bin/alembic", line 8, in <module>
    load_entry_point('alembic==0.6.5', 'console_scripts', 'alembic')()
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/config.py", line 298, in main
    CommandLine(prog=prog).main(argv=argv)
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/config.py", line 293, in main
    self.run_cmd(cfg, options)
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/config.py", line 279, in run_cmd
    **dict((k, getattr(options, k)) for k in kwarg)
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/command.py", line 125, in upgrade
    script.run_env()
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/script.py", line 203, in run_env
    util.load_python_file(self.dir, 'env.py')
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/util.py", line 212, in load_python_file
    module = load_module_py(module_id, path)
  File "/mnt/home/dmonego/test/local/lib/python2.7/site-packages/alembic/compat.py", line 58, in load_module_py
    mod = imp.load_source(module_id, path, fp)
  File "alembic/env.py", line 19, in <module>
    from gen9db.schema import metadata
ImportError: No module named schema

这是在上下文中运行的pdb会话：

(test)dmonego@server:~/db/scripts$ alembic upgrade +1
> /mnt/home/dmonego/db/scripts/alembic/env.py(17)<module>()
-> import db
(Pdb) import db
(Pdb) import db.schema
*** ImportError: No module named schema
(Pdb) from db import schema
(Pdb) type(schema)
<type 'module'>

换句话说，脚本在尝试使用module.submodule语法时会死亡，但子模块存在于模块中，可以使用＆＃34; from module import submodule＆＃34;语法。

这里的解决方法非常明显，但我对这种区别存在感到有些惊讶。什么是＆＃34;来自进口b＆＃34;语法有何不同可能会导致此问题？

“import module.submodule”和“from module import submodule”之间有什么区别？

0 个答案: