Python：为什么不加载此子模块？

Question

I installed scikit-learn with pip ( pip install -U scikit-learn ). I then went to ipython and ran import sklearn , but if I then try to load any modules, they aren't found. In particular, the tab completion of sklearn doesn't seem correct:

In [2]: sklearn.
sklearn.base          sklearn.clone         sklearn.externals     sklearn.re            sklearn.setup_module  sklearn.sys           sklearn.test          sklearn.warnings 

Any idea what's going on here? Other modules load fine. For example, numpy works normally.

Answer 1

Import the submodule you want to use explicitly:

import sklearn.<submodule>
print sklearn.<submodule>.function()

or

from sklearn.<submodule> import function
print function()

In large python packages, oftentimes the submodules need to be explicitly imported. This is so that the user can pick and choose what to import without importing the entire package (which can negatively affect startup time).