Develop Reference

Different module import in Mac python vs. spyder

I have recently asked this question about importing an arbitrary amount of modules in python. I received two good answers. Both worked when I programmed it in spyder.
Today I ran the script from my terminal as test, since I'm planning to move my code to my server. But this time the script crashed with this Traceback:
File "evaluation.py", line 27, in __init__
self.solvers.append( __import__(file_name[:-3]) ) #cut away .py
ImportError: No module named 'v00'
The file architecture looks like this:
-evaluation.py
-evaluation
-v00.py
-v01.py
The code in evaluation.py which causes trouble is this one:
os.chdir('evaluation')
for file_name in glob.glob("*.py"):
self.solvers.append( __import__(file_name[:-3]) ) #cut away .py
for idx, solver in enumerate(self.solvers):
self.dqn.append(solver.DQNSolver() )
Why does this work in spyder but not in the terminal? They both use python 3.5 and I double checked that both are in the folder "evaluation" when executing the malicious line.

The typical way to handle this would be to turn the folder into a package by adding an empty __init__.py file and then import from the package with import evaluation.v00 (or the equivalent __import__ function call). But you may run into problems as your main script has the same name as the package. I would suggest renaming one or the other
-evaluationscript.py
-evaluation
-__init__.py (empty file)
-v00.py
-v01.py
And then you probably need to use import_module instead of __import__ to populate solvers with the actual module (instead of the package).
I'm not familiar with spyder, but if the same code is working there, then it may be adding the evaluation folder to the search path either with the PYTHONPATH env var, or by modifying sys.path.
When you run a script, the path of the script is added to the default search path for module imports, but changing the folder using os.chdir won't affect that search path.

make Python program runnable from everywhere

I wrote a small python program and again I am struggling with producing a good structure.
A few days ago I read a blog and many other websites, which advise against from a import b imports and recommend to use always import a.b "project absolute" path (the whole path from the project root to what I want to import) imports. That as a background.
I included a __main__.py so that I can run my program with python -m <directory>, which was another recommendation of someone on stackoverflow in one of the hundreds of python import questions. It is supposed to help keeping code runnable and testable with the same import structure, which was a problem in another project of mine.
Now what I want it, that from anywhere in my system, I can run python -m <dir of my code> and not only from one directory up the RSTCitations directory.
How can I achieve that, without:
python path manipulations (which are a dirty hack)
changing my imports somehow and getting a not recommended import structure
doing other dark magic to my code
I want to stick to best practices in organizing my code but still want it to be runnable from wherever I am in the terminal.
Example of fail
When I run the program as described from another directory completely unrelated to my program, I get for example the following error:
/home/user/development/anaconda3/bin/python: No module named /home/user/development/rst-citations-to-raw-latex/RSTCitations
However the path is correct. That is exactly where the code is.

You can :
install your program with pip ( see Installing Python packages from local file system folder with pip )
put your module in the python import path (and/or edit PYTHONPATH in the environment for the users that need to use it)
If you don't need other users to 'import' your library but just use it as a standalone program, you can also just put a symlink/script to your program, makeing it runnable from a directory which is in your PATH.

Can you import a Python module from a Windows symbolic link?

I'm contributing to a Python 3 project from a Windows 7 computer.
In order to minimise clutter while making and testing changes, I'm placing a few test files inside a folder called ignore within the project, and excluding it from the version control system (Git).
There is no __init__.py file in the root of the project, so I thought I'd create a symbolic link from the module I want to test into the ignore folder, to enable me to import it.
mklink ignore\example.py example.py
When I try to import the module from a script in ignore I get an ImportError saying the example module doesn't exist.
Is it possible to import modules via symbolic links in this way? I understand that this is supposed to work, but I can't find a reference saying that it works on Windows.

I have just spent +2 hours trying to resolve this issue and
it turned out that creating a Windows Directory Junction worked for me.
You don't need to use a relative one, it worked with both.
So first create an empty file __init__.py in your igonore-folder
then in the elevated mode (As Administrator) create a link:
mklink /J ignore path-to-your-ignore-module
Then in your Python code you would be able to execute:
from ignore.something import some-other-thing

Python can't find module in the same folder

My python somehow can't find any modules in the same directory.
What am I doing wrong? (python2.7)
So I have one directory '2014_07_13_test', with two files in it:
test.py
hello.py
where hello.py:
# !/usr/local/bin/python
# -*- coding: utf-8 -*-
def hello1():
print 'HelloWorld!'
and test.py:
# !/usr/local/bin/python
# -*- coding: utf-8 -*-
from hello import hello1
hello1()
Still python gives me
>>> Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<string>", line 4, in <module>
ImportError: No module named hello
What's wrong?

Change your import in test.py to:
from .hello import hello1

Your code is fine, I suspect your problem is how you are launching it.
You need to launch python from your '2014_07_13_test' directory.
Open up a command prompt and 'cd' into your '2014_07_13_test' directory.
For instance:
$ cd /path/to/2014_07_13_test
$ python test.py
If you cannot 'cd' into the directory like this you can add it to sys.path
In test.py:
import sys, os
sys.path.append('/path/to/2014_07_13_test')
Or set/edit the PYTHONPATH
And all should be well...
...well there is a slight mistake with your 'shebang' lines (the first line in both your files), there shouldn't be a space between the '#' and the '!'
There is a better shebang you should use.
Also you don't need the shebang line on every file... only the ones you intend to run from your shell as executable files.

I had a similar problem, I solved it by explicitly adding the file's directory to the path list:
import os
import sys
file_dir = os.path.dirname(__file__)
sys.path.append(file_dir)
After that, I had no problem importing from the same directory.

Here is the generic solution I use. It solves the problem for importing from modules in the same folder:
import os.path
import sys
sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
Put this at top of the module which gives the error "No module named xxxx"

In my case, Python was unable to find it because I'd put the code inside a module with hyphens, e.g. my-module. When I changed it to my_module it worked.

I ran into this issue. I had three folders in the same directory so I had to specify which folder.
Ex: from Folder import script

I had somewhat of a similar problem. I could not import modules even though they all were in the same directory (importError). I tried out the solutions above but none of them worked for me. I had to set up the path myself (manually). Also, the code was run on my university server, perhaps that's why I had to set the path manually.
import sys
sys.path.append(r'path_to_directory_where_all_modules_are')
I recommend reading The Module Search Path

The following doesn't solve the OP's problem, but the title and error is exactly what I faced.
If your project has a setup.py script in it, you can install that package you are in, with python3 -m pip install -e . or python3 setup.py install or python3 setup.py develop, and this package will be installed, but still editable (so changes to the code will be seen when importing the package). If it doesn't have a setup.py, make sense of it.
Anyway, the problem OP faces seems to not exist anymore?
file one.py:
def function():
print("output")
file two.py:
#!/usr/bin/env python3
import one
one.function()
chmod +x two.py # To allow execution of the python file
./two.py # Only works if you have a python shebang
Command line output: output
Other solutions seem 'dirty'
In the case of OP with 2 test files, modifying them to work is probably fine. However, in other real scenarios, the methods listed in the other answers is probably not recommended. They require you to modify the python code or restrict your flexibility (running the python file from a specific directory) and generally introduce annoyances. What if you've just cloned a project, and this happens? It probably already works for other people, and making code changes is unnecessary. The chosen answer also wants people to run a script from a specific folder to make it work. This can be a source of long term annoyance, which is never good. It also suggests adding your specific python folder to PATH (can be done through python or command line). Again, what happens if you rename or move the folder in a few months? You have to hunt down this page again, and eventually discover you need to set the path (and that you did exactly this a few months ago), and that you simply need to update a path (sure you could use sys.path and programmatically set it, but this can be flaky still). Many sources of great annoyance.

If you are sure that all the modules, files you're trying to import are in the same folder and they should be picked directly just by giving the name and not the reference path then your editor or terminal should have opened the main folder where all the files/modules are present.
Either, try running from Terminal, make sure first you go to the correct directory.
cd path to the root folder where all the modules are
python script.py
Or if running [F5] from the editor i.e VsCode then open the complete folder there and not the individual files.

After spending hours to get imports working like:
from business import Business
from .business import Business
import .Business
import business.Business
...
I got finally rid of my embedded python installation and installed python from the scratch by be the .exe file for all users like in
c:\Program Files\Python310
then I made sure my PATH Variable is up to date with the new installation (so what we want to see or make are entries like c:\Program Files\Python310 and c:\Program Files\Python310\Scripts and %USERPROFILE%\AppData\Roaming\Python\Python310\Scripts) and started a cmd with administrator privileges, downloaded the get-pip.py file and run it in the elivated cmd like python get-pip.py and finaly everything worked as expected... I don't know why or what I did wrong or so, but python really seems that it need to be integrated deeply into windows or it just do not work the easy way. It doesn't happen too often, but in this case it worked a lot better in linux ;)

Also recheck spelling of both the file and the module for typos.
For example
import passwords
When the file name has been saved as password missing an s.
It might sound obvious but it can sometimes be something as simple as this when all other advice above not working :)

This kind of problems happens when your project path is changed. You need to use:
cd path\to\the\files_path
simply

The same error, but I didn't find an answer to my case, maybe someone need my solution.
It appears that in PyCharm I've created .py file, but somehow in windows directory of my project file was blank and without .py. So I rename extension right in derictory and it worked.
Picture before changing an extension

Python error "ImportError: No module named"

Python is installed in a local directory.
My directory tree looks like this:
(local directory)/site-packages/toolkit/interface.py
My code is in here:
(local directory)/site-packages/toolkit/examples/mountain.py
To run the example, I write python mountain.py, and in the code I have:
from toolkit.interface import interface
And I get the error:
Traceback (most recent call last):
File "mountain.py", line 28, in ?
from toolkit.interface import interface
ImportError: No module named toolkit.interface
I have already checked sys.path and there I have the directory /site-packages. Also, I have the file __init__.py.bin in the toolkit folder to indicate to Python that this is a package. I also have a __init__.py.bin in the examples directory.
I do not know why Python cannot find the file when it is in sys.path. Any ideas? Can it be a permissions problem? Do I need some execution permission?

Based on your comments to orip's post, I guess this is what happened:
You edited __init__.py on windows.
The windows editor added something non-printing, perhaps a carriage-return (end-of-line in Windows is CR/LF; in unix it is LF only), or perhaps a CTRL-Z (windows end-of-file).
You used WinSCP to copy the file to your unix box.
WinSCP thought: "This has something that's not basic text; I'll put a .bin extension to indicate binary data."
The missing __init__.py (now called __init__.py.bin) means python doesn't understand toolkit as a package.
You create __init__.py in the appropriate directory and everything works... ?

Does
(local directory)/site-packages/toolkit
have a __init__.py?
To make import walk through your directories every directory must have a __init__.py file.

I ran into something very similar when I did this exercise in LPTHW; I could never get Python to recognise that I had files in the directory I was calling from. But I was able to get it to work in the end. What I did, and what I recommend, is to try this:
(NOTE: From your initial post, I am assuming you are using an *NIX-based machine and are running things from the command line, so this advice is tailored to that. Since I run Ubuntu, this is what I did)
Change directory (cd) to the directory above the directory where your files are. In this case, you're trying to run the mountain.py file, and trying to call the toolkit.interface.py module, which are in separate directories. In this case, you would go to the directory that contains paths to both those files (or in other words, the closest directory that the paths of both those files share). Which in this case is the toolkit directory.
When you are in the toolkit directory, enter this line of code on your command line:
export PYTHONPATH=.
This sets your PYTHONPATH to ".", which basically means that your PYTHONPATH will now look for any called files within the directory you are currently in, (and more to the point, in the sub-directory branches of the directory you are in. So it doesn't just look in your current directory, but in all the directories that are in your current directory).
After you've set your PYTHONPATH in the step above, run your module from your current directory (the toolkit directory). Python should now find and load the modules you specified.

On *nix, also make sure that PYTHONPATH is configured correctly, especially that it has this format:
.:/usr/local/lib/python
(Mind the .: at the beginning, so that it can search on the current directory, too.)
It may also be in other locations, depending on the version:
.:/usr/lib/python
.:/usr/lib/python2.6
.:/usr/lib/python2.7 and etc.

You are reading this answer says that your __init__.py is in the right place, you have installed all the dependencies and you are still getting the ImportError.
I was facing a similar issue except that my program would run fine when ran using PyCharm but the above error when I would run it from the terminal. After digging further, I found out that PYTHONPATH didn't have the entry for the project directory. So, I set PYTHONPATH per Import statement works on PyCharm but not from terminal:
export PYTHONPATH=$PYTHONPATH:`pwd` (OR your project root directory)
There's another way to do this using sys.path as:
import sys
sys.path.insert(0,'<project directory>') OR
sys.path.append('<project directory>')
You can use insert/append based on the order in which you want your project to be searched.

Using PyCharm (part of the JetBrains suite) you need to define your script directory as Source:
Right Click > Mark Directory as > Sources Root

For me, it was something really stupid. I installed the library using pip3 install but was running my program as python program.py as opposed to python3 program.py.

I solved my own problem, and I will write a summary of the things that were wrong and the solution:
The file needs to be called exactly __init__.py. If the extension is different such as in my case .py.bin then Python cannot move through the directories and then it cannot find the modules. To edit the files you need to use a Linux editor, such as vi or nano. If you use a Windows editor this will write some hidden characters.
Another problem that was affecting it was that I had another Python version installed by the root, so if someone is working with a local installation of python, be sure that the Python installation that is running the programs is the local Python. To check this, just do which python, and see if the executable is the one that is in your local directory. If not, change the path, but be sure that the local Python directory is before than the other Python.

To mark a directory as a package you need a file named __init__.py, does this help?

an easy solution is to install the module using python -m pip install <library-name> instead of pip install <library-name>
you may use sudo in case of admin restrictions

To all those who still have this issue. I believe Pycharm gets confused with imports. For me, when i write 'from namespace import something', the previous line gets underlined in red, signaling that there is an error, but works. However ''from .namespace import something' doesn't get underlined, but also doesn't work.
Try
try:
from namespace import something
except NameError:
from .namespace import something

Yup. You need the directory to contain the __init__.py file, which is the file that initializes the package. Here, have a look at this.
The __init__.py files are required to make Python treat the directories as containing packages; this is done to prevent directories with a common name, such as string, from unintentionally hiding valid modules that occur later on the module search path. In the simplest case, __init__.py can just be an empty file, but it can also execute initialization code for the package or set the __all__ variable, described later.

If you have tried all methods provided above but failed, maybe your module has the same name as a built-in module. Or, a module with the same name existing in a folder that has a high priority in sys.path than your module's.
To debug, say your from foo.bar import baz complaints ImportError: No module named bar. Changing to import foo; print foo, which will show the path of foo. Is it what you expect?
If not, Either rename foo or use absolute imports.

You must have the file __ init__.py in the same directory where it's the file that you are importing.
You can not try to import a file that has the same name and be a file from 2 folders configured on the PYTHONPATH.
eg:
/etc/environment
PYTHONPATH=$PYTHONPATH:/opt/folder1:/opt/folder2
/opt/folder1/foo
/opt/folder2/foo
And, if you are trying to import foo file, python will not know which one you want.
from foo import ... >>> importerror: no module named foo

My two cents:
Spit:
Traceback (most recent call last):
File "bash\bash.py", line 454, in main
import bosh
File "Wrye Bash Launcher.pyw", line 63, in load_module
mod = imp.load_source(fullname,filename+ext,fp)
File "bash\bosh.py", line 69, in <module>
from game.oblivion.RecordGroups import MobWorlds, MobDials, MobICells, \
ImportError: No module named RecordGroups
This confused the hell out of me - went through posts and posts suggesting ugly syspath hacks (as you see my __init__.py were all there). Well turns out that game/oblivion.py and game/oblivion was confusing python
which spit out the rather unhelpful "No module named RecordGroups". I'd be interested in a workaround and/or links documenting this (same name) behavior -> EDIT (2017.01.24) - have a look at What If I Have a Module and a Package With The Same Name? Interestingly normally packages take precedence but apparently our launcher violates this.
EDIT (2015.01.17): I did not mention we use a custom launcher dissected here.

Fixed my issue by writing print (sys.path) and found out that python was using out of date packages despite a clean install. Deleting these made python automatically use the correct packages.

In my case, because I'm using PyCharm and PyCharm create a 'venv' for every project in project folder, but it is only a mini env of python. Although you have installed the libraries you need in Python, but in your custom project 'venv', it is not available. This is the real reason of 'ImportError: No module named xxxxxx' occurred in PyCharm.
To resolve this issue, you must add libraries to your project custom env by these steps:
In PyCharm, from menu 'File'->Settings
In Settings dialog, Project: XXXProject->Project Interpreter
Click "Add" button, it will show you 'Available Packages' dialog
Search your library, click 'Install Package'
Then, all you needed package will be installed in you project custom 'venv' folder.
Enjoy.

Linux: Imported modules are located in /usr/local/lib/python2.7/dist-packages
If you're using a module compiled in C, don't forget to chmod the .so file after sudo setup.py install.
sudo chmod 755 /usr/local/lib/python2.7/dist-packages/*.so

In my case, the problem was I was linking to debug python & boost::Python, which requires that the extension be FooLib_d.pyd, not just FooLib.pyd; renaming the file or updating CMakeLists.txt properties fixed the error.

My problem was that I added the directory with the __init__.py file to PYTHONPATH, when actually I needed to add its parent directory.

For me, running the file as a module helped.
Instead of
python myapp/app.py
using
python -m myapp.app
It's not exactly the same but it might be a better approach in some cases.

If you are using a setup script/utility (e.g. setuptools) to deploy your package, don't forget to add the respective files/modules to the installer.
When supported, use find_packages() or similar to automatically add new packages to the setup script. This will absolutely save you from a headache, especially if you put your project aside for some time and then add something later on.
import setuptools
setuptools.setup(
name="example-pkg",
version="0.0.1",
author="Example Author",
author_email="author#example.com",
description="A small example package",
packages=setuptools.find_packages(),
classifiers=[
"Programming Language :: Python :: 3",
"Operating System :: OS Independent",
],
python_requires='>=3.6',
)
(Example taken from setuptools documentation)

I had the same problem (Python 2.7 Linux), I have found the solution and i would like to share it. In my case i had the structure below:
Booklet
-> __init__.py
-> Booklet.py
-> Question.py
default
-> __init_.py
-> main.py
In 'main.py' I had tried unsuccessfully all the combinations bellow:
from Booklet import Question
from Question import Question
from Booklet.Question import Question
from Booklet.Question import *
import Booklet.Question
# and many othet various combinations ...
The solution was much more simple than I thought. I renamed the folder "Booklet" into "booklet" and that's it. Now Python can import the class Question normally by using in 'main.py' the code:
from booklet.Booklet import Booklet
from booklet.Question import Question
from booklet.Question import AnotherClass
From this I can conclude that Package-Names (folders) like 'booklet' must start from lower-case, else Python confuses it with Class names and Filenames.
Apparently, this was not your problem, but John Fouhy's answer is very good and this thread has almost anything that can cause this issue. So, this is one more thing and I hope that maybe this could help others.

In linux server try dos2unix script_name
(remove all (if there is any) pyc files with command find . -name '*.pyc' -delete)
and re run in the case if you worked on script on windows

In my case, I was using sys.path.insert() to import a local module and was getting module not found from a different library. I had to put sys.path.insert() below the imports that reported module not found. I guess the best practice is to put sys.path.insert() at the bottom of your imports.

I've found that changing the name (via GUI) of aliased folders (Mac) can cause issues with loading modules. If the original folder name is changed, remake the symbolic link. I'm unsure how prevalent this behavior may be, but it was frustrating to debug.

another cause makes this issue
file.py
#!/bin/python
from bs4 import BeautifulSoup
if your default python is pyyhon2
$ file $(which python)
/sbin/python: symbolic link to python2
file.py need python3, for this case(bs4)
you can not execute this module with python2 like this:
$ python file.py
# or
$ file.py
# or
$ file.py # if locate in $PATH
Tow way to fix this error,
# should be to make python3 as default by symlink
$ rm $(which python) && ln -s $(which python3) /usr/bin/python
# or use alias
alias python='/usr/bin.../python3'
or change shebang in file.py to
#!/usr/bin/...python3

After just suffering the same issue I found my resolution was to delete all pyc files from my project, it seems like these cached files were somehow causing this error.
Easiest way I found to do this was to navigate to my project folder in Windows explorer and searching for *.pyc, then selecting all (Ctrl+A) and deleting them (Ctrl+X).
Its possible I could have resolved my issues by just deleting the specific pyc file but I never tried this

I faced the same problem: Import error. In addition the library've been installed 100% correctly. The source of the problem was that on my PC 3 version of python (anaconda packet) have been installed). This is why the library was installed no to the right place. After that I just changed to the proper version of python in the my IDE PyCharm.

I had the same error. It was caused by somebody creating a folder in the same folder as my script, the name of which conflicted with a module I was importing from elsewhere. Instead of importing the external module, it looked inside this folder which obviously didn't contain the expected modules.