Pythonのクラス定義のファイルの場所を知る。

ipythonの%pinfoを使いましょう

~/Documents/.../python/numpy $ ipython                                                        git[branch:master]
from sklearn.ensemble import RandomForestClassifier, ExtraTreesClassifierPython 2.7.3 (default, Apr 13 2012, 00:05:08) 
Type "copyright", "credits" or "license" for more information.

IPython 0.13 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: from sklearn.ensemble import RandomForestClassifier, ExtraTreesClassifier

In [2]: %p
%%perl      %paste      %pdef       %pinfo      %pprint     %prun       %pushd      %pylab      
%%prun      %pastebin   %pdoc       %pinfo2     %precision  %psearch    %pwd        
%page       %pdb        %pfile      %popd       %profile    %psource    %pycat      

In [2]: %pinfo RandomForestClassifier

String Form:<class 'sklearn.ensemble.forest.RandomForestClassifier'>
File:       /Library/Python/2.7/site-packages/scikit_learn-0.13.1-py2.7-macosx-10.8-intel.egg/sklearn/ensemble/forest.py
Docstring:
A random forest classifier.

A random forest is a meta estimator that fits a number of classifical
decision trees on various sub-samples of the dataset and use averaging
to improve the predictive accuracy and control over-fitting.

...