为什么python会出现AttributeError?
问题说明
有一件事，我不明白.
为什么会这样
import scipy # happens with several other modules, too. I took scipy as an example now...
matrix = scipy.sparse.coo_matrix(some_params)
产生这个错误:
AttributeError: 'module' object has no attribute 'sparse'
正确答案
发生这种情况是因为 scipy 模块没有任何名为 sparse 的属性.该属性仅在您 import scipy.sparse 时定义.
This happens because the scipy module doesn't have any attribute named sparse. That attribute only gets defined when you import scipy.sparse.
当你只是 import scipy 时，子模块不会自动被导入；您需要明确导入它们.大多数包也是如此，尽管包可以根据需要选择导入自己的子模块.(例如，如果 scipy/__init__.py 包含一个语句 import scipy.sparse，则sparse 子模块每当您导入 scipy 时都会被导入.)
Submodules don't automatically get imported when you just import scipy; you need to import them explicitly. The same holds for most packages, although a package can choose to import its own submodules if it wants to. (For example, if scipy/__init__.py included a statement import scipy.sparse, then the sparse submodule would be imported whenever you import scipy.)
这篇好文章是转载于：学新通技术网
