Access a hidden library function in Python? - function

Question

So when I was doing coding I came across this:
from hidden_lib import train_classifier
Out of curiosity, is there a way to access the function using the terminal and see what's inside there?

Answer 1

You can use "inspect" library to do that, but it will work only if you have the source code of the "hidden_lib" somewhere on your machine:
>>> import hidden_lib
>>> import inspect
>>> print inspect.getsource(hidden_lib.train_classifier)
Otherwise library will throw the exception:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\inspect.py", line 701, in getsource
lines, lnum = getsourcelines(object)
File "C:\Python27\lib\inspect.py", line 690, in getsourcelines
lines, lnum = findsource(object)
File "C:\Python27\lib\inspect.py", line 529, in findsource
raise IOError('source code not available')
IOError: source code not available
In such a case you need to decompile .pyc file first. To do that you need to go to the:
https://github.com/wibiti/uncompyle2
then download the package, go to the package folder and install it:
C:\package_location> C:\Python27\python.exe setup.py install
Now you can easily find location of the library by typing [1]:
>>> hidden_lib.__file__
Then go to the pointed directory and unpyc the file:
>C:\Python27\python.exe C:\Python27\Scripts\uncompyle2 -o C:\path_pointed_by_[1]\hidden_lib.py C:\path_pointed_by_[1]\hidden_lib.pyc
Sources should be decompiled seccessfully:
# 2016.05.07 17:47:36 Central European Daylight Time
+++ okay decompyling hidden_lib.pyc
# decompiled 1 files: 1 okay, 0 failed, 0 verify faile
# 2016.05.07 17:47:36 Central European Daylight Time
And now you can display sources of functions exposed by hidden_lib in a way I described at the beginning of the post. If you are using iPython you can use also embedded function help(hidden_lib.train_classifier) to do exactly the same.
IMPORTANT NOTE: uncompyle2 library (that I used) works only with Python 2.7, if you want to do the same for Python 3.x you need to find other similar library.