How do I find the location of Python module sources?
How do I learn where the source file for a given Python module is installed? Is the method different on Windows than on Linux?
I'm trying to look for the source of the datetime
module in particular, but I'm interested in a more general answer as well.
For a pure python module you can find the source by looking at themodule.__file__
. The datetime module, however, is written in C, and therefore datetime.__file__
points to a .so file (there is no datetime.__file__
on Windows), and therefore, you can't see the source.
If you download a python source tarball and extract it, the modules' code can be found in the Modules subdirectory.
For example, if you want to find the datetime code for python 2.6, you can look at
Python-2.6/Modules/datetimemodule.c
You can also find the latest Mercurial version on the web at https://hg.python.org/cpython/file/tip/Modules/_datetimemodule.c
Running python -v
from the command line should tell you what is being imported and from where. This works for me on Windows and Mac OS X.
C:>python -v
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# C:Python24libsite.pyc has bad mtime
import site # from C:Python24libsite.py
# wrote C:Python24libsite.pyc
# C:Python24libos.pyc has bad mtime
import os # from C:Python24libos.py
# wrote C:Python24libos.pyc
import nt # builtin
# C:Python24libntpath.pyc has bad mtime
...
I'm not sure what those bad mtime's are on my install!
I realize this answer is 4 years late, but the existing answers are misleading people.
The right way to do this is never __file__
, or trying to walk through sys.path
and search for yourself, etc. (unless you need to be backward compatible beyond 2.1).
It's the inspect
module—in particular, getfile
or getsourcefile
.
Unless you want to learn and implement the rules (which are documented, but painful, for CPython 2.x, and not documented at all for other implementations, or 3.x) for mapping .pyc
to .py
files; dealing with .zip archives, eggs, and module packages; trying different ways to get the path to .so
/ .pyd
files that don't support __file__
; figuring out what Jython/IronPython/PyPy do; etc. In which case, go for it.
Meanwhile, every Python version's source from 2.0+ is available online at http://hg.python.org/cpython/file/XY/
(eg, 2.7 or 3.3). So, once you discover that inspect.getfile(datetime)
is a .so
or .pyd
file like /usr/local/lib/python2.7/lib-dynload/datetime.so
, you can look it up inside the Modules directory. Strictly speaking, there's no way to be sure of which file defines which module, but nearly all of them are either foo.c
or foomodule.c
, so it shouldn't be hard to guess that datetimemodule.c is what you want.
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