Related
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.
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)
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.
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.
I have python 3.10 project that uses a combination of scraping websites, data analysis, and additional APIs. Some utility modules may be used by the scraping and data analysis modules. I'm fundamentally misunderstanding something about how imports work in Python.
For example, in sl_networking.py, I try to import the Result class from result.py:
from ...util.result import Result
Producing the error:
PS C:\Development\TradeAssist> & c:/Development/TradeAssist/.venv/Scripts/python.exe c:/Development/TradeAssist/libs/scrapers/sl/sl_networking.py
Traceback (most recent call last):
File "c:\Development\TradeAssist\libs\scrapers\sl\sl_networking.py", line 1, in <module>
from ...util.result import Result
ImportError: attempted relative import with no known parent package
The project structure I'm currently using is:
TradeAssist
|__libs
| |__broker_apis
| | |__ibapi
| |__data_analysis
| | |__sl
| | |__ta
| |__scrapers
| | |__sl
| | | | sl_auth.py
| | | |__sl_networking.py
| | |__ta
| |__util
| |__result.py
|__tests
|__test_sl.py
|__test_ta.py
If I have a common utility function that I expect to use within the data_analysis and scraper modules, how should I be structuring my project and handling imports?
This is not a Python question, but rather a VSCode question. The way VSCode runs Python files by default is a little bit dumb. When you click the little triangle to "Run Python File" on test_sl, VSCode will run a command such as this:
/usr/local/bin/python3 /path/to/TradeAssist/tests/test_ta.py
Python by default initialises sys.path to contain the directory containing the file being run, in addition to its own libraries, and whatever is in your PYTHONPATH variable. This means your sys.path looks something like this (with ... being Python's libraries)
['/path/to/TradeAssist/tests', ...]
However, this means code in lib is not reachable; only files inside tests will be correctly found by Python. I.e. out of the box, VSCode is only able to run Python files that are in your root source folder (e.g. src, or directly in the root workspace folder).
There are several solutions.
The first one is simplest: decide that your TradeAssist is the source root, and put any files you want to execute directly there. They will be able to import any files under them, and the files under them will be able to use both relative and absolute imports correctly. This has obvious disadvantages — you would be self-limiting yourself to one directory.
The second is to set up VSCode to tell Python where your source root(s) are, by defining PYTHONPATH. This is fairly complex.
The third is the simplest, and likely the correct case here: use VSCode's testing functionality. Configure the testing framework (presumably using unittest and test_*.py test file pattern), then just run the tests. If you consider TradeAssist to be your source root, it will work correctly (i.e. import libs.scrapers.sl.sl_networking will work correctly inside your tests, and from ...util.result import Result will work correctly inside your sl_networking.py). The testing function will take care of running the tests for you in a correct fashion.
However, if you want to consider libs to be your source root (i.e. you would like to do import scrapers.sl.sl_networking), or if you want to be able to run arbitrary files, not just tests, then you have to fall back to method #2: messing with PYTHONPATH.
tl;dr: Don't run test files manually, let VSCode do it for you by setting up tests correctly.
Relative imports only work when the code is executed from the outermost parent root. In the current scenario, you can only execute the code at or above libs directory.
python -m scrapers.sl.sl_networking
should work fine if you are running this at libs directory.
Once the project is structured, it is easy to run the individual scripts from the top parent directory using -m flag, as no refactoring will be required. If the code has to be executed from the script parent directory, the following has to be done:
Use absolute imports instead of relative imports.
Add the directory to the path python searches for imports. This can be done in several ways. Add it to the PYTHONPATH env variable or use any of the sys.path.append or sys.path.insert hacks, which can be easily found.
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.
Given a github project with the following structure:
mylib/
package1/
package2/
...
packagen/
scripts/
x/a.py
x/b.py
.....
.....
x/z.py
In the scripts directory there many scripts in many subfolders.
In these scripts the packages of mylib are used.
The problem is that somehow we have to tell python where the lib directories are. Otherwise i cannot import the modules.
The solutions in the web i found are not satisfying
Solution 1: Use the sys library:
import sys
sys.path.insert(0,"..\..")
from mylib.package1 import classX
This is not good because i have to write it in every script and if i change the directory structure everything has to be modified
Solution2: Change the PYTHONPATH
This is also not good because i want to collaborate with my friends and i don't want to tell them to change the python path
Is there a better solution?
Create a virtualenv, install all the packages in that virtualenv and execute all the scripts using it.
You could provide a requirements.txt file or a script that creates the virtualenv, so that it is easy for your friends to use it.
Here is a tutorial.
I've worked on several medium-sized python applications to date, and every time it seems like I cobble together a terrible system of imports from tangential Stack Overflow answers and half-understood blog posts. It's ugly and hard to maintain and ultimately very unsatisfying. With this question I attempt to put all that behind me.
Say I have a python application split into the following files:
app.py
constants.py
ui/window.py
web/connection.py
With the following include requirements:
app.py needs to include window.py and connection.py
window.py needs to include constants.py and connection.py
connection.py needs to include constants.py
app.py is the starting point for the application, but window.py and connection.py are also invokable from the command line to test basic functionality (ideally from within their respective folders).
What combination of __init__.py files, carefully crafted import statements and wacky python path magic will allow me to achieve this structure?
Thanks very much,
--Dan
It really helps if, instead of thinking in terms of "file structure" first and then trying to figure out the packages, you design things in terms of packages, and then lay out your file structure to implement those packages.
But if you want to know how to hack up what you already have: If you put this at the top level (that is, in one of the paths on your sys.path), and create files names ui/__init__.py and web/__init__.py, then:
app.py can be run as a script.
app.py can be run with -m app.
app.py can be imported with import app.
window.py cannot be run directly.
window.py can be run with -m ui.window.
window.py can be imported with import ui.window.
connection.py cannot be run directly.
connection.py can be run with -m web.connection.
connection.py can be imported with import web.connection.
No wacky path magic is needed; you just need the top level (with app.py, constants.py, ui, and web) to be on your sys.path—which it automatically is when you run with that directory as your working directory, or install everything directly into site-packages, or install it as an egg, etc.
That's as close as you're going to get to what you want. You do ever want to run code with a package directory as your current working directory or otherwise on sys.path, so don't even try. If you think you need that, what you probably want is to separate the runnable code out into a script that you can put at the top level, or somewhere entirely separate. (For example, look at pip or ipython, which installs scripts into somewhere on your system $PATH that do nothing but import some module and run a function.)
The only other thing you might want to consider is putting all of this into a package, say, myapp. You do that by adding a top-level __init__.py, and then running from the parent directory, and adding myapp. to the start of all your importand -m statements. That means you can no longer run app.py as a script either, so again you will need to split the script code out into a separate file from the module that does all the work.
You can use that structure with just a small modification: add empty __init__.py files to the ui/ and web/ directory. Then, where you would have done import window, do either import ui.window, or from ui import window. Similarly, change import connection to import web.connection or from web import connection.
Rationale: Python doesn't work so much with directories as it does with packages, which are directories with an __init__.py in them. By changing ui and web to be packages, you don't have to do any particular Python path magic to work with them, and you get the benefit of adding some structure to your modules and imports. That will become particularly important if you start having modules with the same name in different directories (e.g. a util.py in both the ui and web directories; not necessarily the cleanest design but you get the idea).
If you invoke window.py or connection.py directly to test them, you need to add the top-level directory to your PYTHONPATH for things to still work – but there is a subtle additional wrinkle. When you run this from the top-level directory:
PYTHONPATH=$PWD python web/connection.py
you now have both the top-level directory on your module path AND the web/ directory. This can cause certain relative imports to do unexpected things.
Another way is to use Python's -m option from the top-level directory:
python -m web.foo
I know many folks like to nail their tests right into the modules like this, but I should also note that there are other ways to structure your tests, particularly with an updated unittest library and tools like nosetests, that will make it a little bit easier to run your tests as your project gets larger. See the skeleton here for a reasonable example:
http://learnpythonthehardway.org/book/ex46.html