I have a Python module and I'd like to get that modules directory from inside itself. I want to do this because I have some files that I'd like to reference relative to the module.
First you need to get a reference to the module inside itself.
mod = sys.__modules__[__name__]
Then you can use __file__ to get to the module file.
mod.__file__
Its directory is a dirname of that.
As you are inside the module all you need is this:
import os
path_to_this_module = os.path.dirname(__file__)
However, if the module in question is actually your programs entry point, then __file__ will only be the name of the file and you'll need to expand the path:
import os
path_to_this_module = os.path.dirname(os.path.abspath(__file__))
I think this is what you are looking for:
import <module>
import os
print os.path.dirname(<module>.__file__)
You should be using pkg_resources for this, the resource* family of functions do just about everything you need without having to muck about with the filesystem.
import pkg_resources
data = pkg_resources.resource_string(__name__, "some_file")
Related
I spent some time researching this and I just cannot work this out in my head.
I run a program in its own directory home/program/core/main.py
In main.py I try and import a module called my_module.py thats located in a different directory, say home/program/modules/my_module.py
In main.py this is how I append to sys.path so the program can be run on anyone's machine (hopefully).
import os.path
import sys
# This should give the path to home/program
sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__), '..'))
# Which it does when checking with
print os.path.join(os.path.abspath(os.path.dirname(__file__), '..')
# So now sys.path knows the location of where modules directory is, it should work right?
import modules.my_module # <----RAISES ImportError WHY?
However if I simply do:
sys.path.append('home/program/modules')
import my_module
It all works fine. But this is not ideal as it now depends on the fact that the program must exist under home/program.
that's because modules isn't a valid python package, probably because it doesn't contain any __init__.py file (You cannot traverse directories with import without them being marked with __init__.py)
So either add an empty __init__.py file or just add the path up to modules so your first snippet is equivalent to the second one:
sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__), '..','modules'))
import my_module
note that you can also import the module by giving the full path to it, using advanced import features: How to import a module given the full path?
Although the answer can be found here, for convenience and completeness here is a quick solution:
import importlib
dirname, basename = os.path.split(pyfilepath) # pyfilepath: /my/path/mymodule.py
sys.path.append(dirname) # only directories should be added to PYTHONPATH
module_name = os.path.splitext(basename)[0] # /my/path/mymodule.py --> mymodule
module = importlib.import_module(module_name) # name space of defined module (otherwise we would literally look for "module_name")
Now you can directly use the namespace of the imported module, like this:
a = module.myvar
b = module.myfunc(a)
I am confused about os module
I have learned that use import to import module.
We have file os.py.
Do we have file os.path.py?
os.path.abspath()
I have read the official Python document.
I did not fully understand what it meant.
I try os.path.abspath("xxx")
I found even the file did not exist, it still returns the path.
ex: os.path.abspath("fadsffefsfgg")
then return
'C:\\Users\\user-t\\fadsffefsfgg'
>>> os.path
<module 'ntpath' from 'C:\\Python34\\lib\\ntpath.py'>
so no, os.path.py doesn't exist. In os module there's probably something like:
import ntpath as path
now the path is os.path.
For your second question, os.path.abspath just prepends the current path to any path if it's not absolute.
It's not a file operation, it's a string operation. It doesn't even check if the file exists, and that's for the best: imagine that you want to create such a file...
Supposing I have written a set of classes to be used in a python file and use them in a script (or python code in a different file). Now both the files require a set of modules to be imported. Should the import be included only once, or in both the files ?
File 1 : my_module.py.
import os
class myclass(object):
def __init__(self,PATH):
self.list_of_directories = os.listdir(PATH)
File 2 :
import os
import my_module
my_module.m = myclass("C:\\User\\John\\Desktop")
list_ = m.list_of_directories
print os.getcwd()
Should I be adding the line import os to both the files ?
How does this impact the performance, supposing there are lots of modules to be imported ? Also, is a module ,once imported, reloaded in this case ?
Each file that you are using a module in, must import that module. Each module is its own namespace. Things you explicitly import within that file are available in that namespace. Thus, if you need os in both files, you should import them in both files.
How can I get the absolute path of an imported module?
As the other answers have said, you can use __file__. However, note that this won't give the full path if the other module is in the same directory as the program. So to be safe, do something like this:
>>> import os
>>> import math
>>> os.path.abspath(math.__file__)
'/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/math.so'
Here's an example with a module I made called checkIP to illustrate why you need to get the abspath (checkIP.py is in the current directory):
>>> import os
>>> import checkIP
>>> os.path.abspath(checkIP.__file__)
'/Users/Matthew/Programs/checkIP.py'
>>> checkIP.__file__
'checkIP.py'
If it is a module within your PYTHONPATH directory tree (and reachable by placing a __init__.py in its directory and parent directories), then call its path attribute.
>>>import sample_module
>>>sample_module.__path__
['/absolute/path/to/sample/module']
You can try:
import os
print os.__file__
to see where the module is located.
I'm using python and virtualenv/pip. I have a module installed via pip called test_utils (it's django-test-utils). Inside one of my django apps, I want to import that module. However I also have another file test_utils.py in the same directory. If I go import test_utils, then it will import this local file.
Is it possible to make python use a non-local / non-relative / global import? I suppose I can just rename my test_utils.py, but I'm curious.
You can switch the search order by changing sys.path:
del sys.path[0]
sys.path.append('')
This puts the current directory after the system search path, so local files won't shadow standard modules.
My problem was even more elaborate:
importing a global/site-packages module from a file with the same name
Working on aero the pm recycler I wanted access to the pip api, in particular pip.commands.search.SearchCommand from my adapter class Pip in source file pip.py.
In this case trying to modify sys.path is useless, I even went as far as wiping sys.path completely and adding the folder .../site-packages/pip...egg/ as the only item in sys.path and no luck.
I would still get:
print pip.__package__
# 'aero.adapters'
I found two options that did eventually work for me, they should work equally well for you:
using __builtin__.__import__() the built-in function
global_pip = __import__('pip.commands.search', {}, {}, ['SearchCommand'], -1)
SearchCommand = global_pip.SearchCommand
Reading the documentation though, suggests using the following method instead.
using importlib.import_module() the __import__ conv wrapper.
The documentation explains that import_module() is a minor subset of functionality from Python 3.1 to help ease transitioning from 2.7 to 3.1
from importlib import import_module
SearchCommand = import_module('pip.commands.search').SearchCommand
Both options get the job done while import_module() definitely feels more Pythonic if you ask me, would you agree?
nJoy!
I was able to force python to import the global one with
from __future__ import absolute_import
at the beginning of the file (this is the default in python 3.0)
You could reset your sys.path:
import sys
first = sys.path[0]
sys.path = sys.path[1:]
import test_utils
sys.path = first + sys.path
The first entry of sys.path is "always" (as in "per default": See python docs) the current directory, so if you remove it you will do a global import.
Since my test_utils was in a django project, I was able to go from ..test_utils import ... to import the global one.
Though, in first place, I would always consider keeping the name of local file not matching with any global module name, an easy workaround, without modifying 'sys.path' can be to include global module in some other file and then import this global module from that file.
Remember, this file must be in some other folder then in the folder where file with name matching with global module is.
For example.
./project/root/workarounds/global_imports.py
import test_utils as tutil
and then in
./project/root/mycode/test_utils.py
from project.root.workarounds.global_imports import tutil
# tutil is global test_utils
# you can also do
from project.root.workarounds.global_imports import test_utils