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Python - ImportError

I have a module I have installed called lts_fits, and this is its path:
~/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/lts_fits
So it is clearly in the site packages folder. Within this folder, there is a python script:
lts_linefit.py
Yet when I have this line of code in my script:
from lts_fits import lts_linefit
I get this error:
ImportError: No module named lts_fits
How? It's clearly in there, and I have tried this same syntax with other random scripts and they import just fine. For instance, a file abc.py located in the folder ~/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/sympy imports just fine when I have the line from sympy import abc. What could be going wrong?

You need an __init__.py file in that directory (you do not have to put anything into the file, all you need to do is create it).
The easiest way to create said file is by using:
touch __init__.py
from within your lts_fits directory in your command line/terminal/console.
See this SO article: What is __init__.py for?
And the Python Documentation for packages.

Create and import a custom python package - import doesn't work in the root

I'm totally new to Python, and I want to create my first Python library for peronal uses.
I'm using Python 2.7.5, and running the IDLE interface.
So far, what I understood from the documentation and related questions is that:
Python goes through a list of directories listed in sys.path to find scripts and libraries
The package directory must contain a __init__.py file, which can be empty
The module I want to create should be a modulename.py file with the code inside the package directory
(Sources: http://www.johnny-lin.com/cdat_tips/tips_pylang/path.html --- https://docs.python.org/2/tutorial/modules.html)
And here is what I tried that fails:
Created a personal package directory C:\....\pythonlibs
Created a subpackage dir C:\....\pythonlibs\package
Created the __init__.py file inside both folders
Created the mymodule.py file in the packacge dir
And then in the IDLE used this code:
import sys
sys.path.append(r'C:\....\pythonlibs')
First issue:
Currently I have to do this append every time I enter the IDLE. How can I keep the directory in sys.path permanently just as there are a lot of other directories there?
Then I tried importing my package:
import pythonlibs #fails!! why?
import pythonlibs.package #fails!! why?
import package #works
The error is: ImportError: No module named pythonlibs
Second issue?
This seems to be against the documentation, why can't I import from the root pythonlibs folder?

With line
sys.path.append(r'C:\....\pythonlibs')
you are instructing interpreter to start looking for modules (libraries) in this directory. Since this directory does not contain pythonlibs folder (the parent does), it can't import it.
Similarly - because it contains the module package, it can import it.

Import module into python not found

I am trying to import the module
import QSTK.qstkutil.qsdateutil as du
But I get the Error
ImportError: No module named QSTK.qstkutil.qsdateutil
My current working directory is
'c:\\Python27\\Lib\\site-packages\\QSTK'
and in the path C:\Python27\Lib\site-packages\QSTK\qstkutil there are the files
qsdateutil.py
qsdateutil.pyc
qsdateutil.pyo

Does importing QSTK work?
import QSTK
How about QSTK.qstkutil?
If not this is most likely a sys.path problem. Please post the result of:
>>>import sys
>>>sys.path
It should look like:
[ [...], 'C:\Python27\Lib\site-packages', [...] ]
Another thing you can check, is if 'C:\Python27\Lib\site-packages\QSTK\qstkutil' contains a file named '__init__.py'. From the module documentation:
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.

try a fresh installation and make sure you run sudo python setup.py install , command after unpack-aging , QSTK. that process links QSTK.qstkutil.qsdateutil.

Can't import my own modules in Python

I'm having a hard time understanding how module importing works in Python (I've never done it in any other language before either).
Let's say I have:
myapp/__init__.py
myapp/myapp/myapp.py
myapp/myapp/SomeObject.py
myapp/tests/TestCase.py
Now I'm trying to get something like this:
myapp.py
===================
from myapp import SomeObject
# stuff ...
TestCase.py
===================
from myapp import SomeObject
# some tests on SomeObject
However, I'm definitely doing something wrong as Python can't see that myapp is a module:
ImportError: No module named myapp

In your particular case it looks like you're trying to import SomeObject from the myapp.py and TestCase.py scripts. From myapp.py, do
import SomeObject
since it is in the same folder. For TestCase.py, do
from ..myapp import SomeObject
However, this will work only if you are importing TestCase from the package. If you want to directly run python TestCase.py, you would have to mess with your path. This can be done within Python:
import sys
sys.path.append("..")
from myapp import SomeObject
though that is generally not recommended.
In general, if you want other people to use your Python package, you should use distutils to create a setup script. That way, anyone can install your package easily using a command like python setup.py install and it will be available everywhere on their machine. If you're serious about the package, you could even add it to the Python Package Index, PyPI.

The function import looks for files into your PYTHONPATH env. variable and your local directory. So you can either put all your files in the same directory, or export the path typing into a terminal::
export PYTHONPATH="$PYTHONPATH:/path_to_myapp/myapp/myapp/"

exporting path is a good way. Another way is to add a .pth to your site-packages location.
On my mac my python keeps site-packages in /Library/Python shown below
/Library/Python/2.7/site-packages
I created a file called awesome.pth at /Library/Python/2.7/site-packages/awesome.pth and in the file put the following path that references my awesome modules
/opt/awesome/custom_python_modules

You can try
from myapp.myapp import SomeObject
because your project name is the same as the myapp.py which makes it search the project document first

You need to have
__init__.py
in all the folders that have code you need to interact with.
You also need to specify the top folder name of your project in every import even if the file you tried to import is at the same level.

In your first myapp directory ,u can add a setup.py file and add two python code in setup.py
from setuptools import setup
setup(name='myapp')
in your first myapp directory in commandline , use pip install -e . to install the package

pip install on Windows 10 defaults to installing in 'Program Files/PythonXX/Lib/site-packages' which is a directory that requires administrative privileges. So I fixed my issue by running pip install as Administrator (you have to open command prompt as administrator even if you are logged in with an admin account). Also, it is safer to call pip from python.
e.g.
python -m pip install <package-name>
instead of
pip install <package-name>

In my case it was Windows vs Python surprise, despite Windows filenames are not case sensitive, Python import is. So if you have Stuff.py file you need to import this name as-is.

let's say i write a module
import os
my_home_dir=os.environ['HOME'] // in windows 'HOMEPATH'
file_abs_path=os.path.join(my_home_dir,"my_module.py")
with open(file_abs_path,"w") as f:
f.write("print('I am loaded successfully')")
import importlib
importlib.util.find_spec('my_module') ==> cannot find
we have to tell python where to look for the module. we have to add our path to the sys.path
import sys
sys.path.append(file_abs_path)
now importlib.util.find_spec('my_module') returns:
ModuleSpec(name='my_module', loader=<_frozen_importlib_external.SourceFileLoader object at 0x7fa40143e8e0>, origin='/Users/name/my_module.py')
we created our module, we informed python its path, now we should be able to import it
import my_module
//I am loaded successfully

This worked for me:
from .myapp import SomeObject
The . signifies that it will search any local modules from the parent module.

Short Answer:
python -m ParentPackage.Submodule
Executing the required file via module flag worked for me. Lets say we got a typical directory structure as below:
my_project:
| Core
->myScript.py
| Utils
->helpers.py
configs.py
Now if you want to run a file inside a directory, that has imports from other modules, all you need to do is like below:
python -m Core.myscript
PS: You gotta use dot notation to refer the submodules(Files/scripts you want to execute). Also I used python3.9+. So I didnt require neither any init.py nor any sys path append statements.
Hope that helps! Happy Coding!

If you use Anaconda you can do:
conda develop /Path/To/Your/Modules
from the Shell and it will write your path into a conda.pth file into the standard directory for 3rd party modules (site-packages in my case).

If you are using the IPython Console, make sure your IDE (e.g., spyder) is pointing to the right working directory (i.e., your project folder)

Besides the suggested solutions like the accepted answer, I had the same problem in Pycharm, and I didn't want to modify imports like the relative addressing suggested above.
I finally found out that if I mark my src/ (root directory of my python codes) as the source in Interpreter settings, the issue will be resolved.

something wrong with my pythonpath

I know this is a dumb question but i'm stumped. My directory structure used to look like this:
-src
|
-module.py
-program.py
when this what my directory structure, I referenced module from program and all was well.
I've since changed my directory structure to this:
-src
|
-__init.py
-module.py
|
-programDir
|
-__init.py
-program.py
now, of course, I can't reach the module from program. How can I reference src as a package. I tried to create an
__init__.py
file in the src directory, but no luck.
Moar deets:
import statements i've tried in program.py:
import module
and
from src import module
the first one worked when the other module and program were in the same directory.
error i'm getting:
ImportError: No module named module
and just for the record: No, my module and program are not called module OR program
update: I've tried this in my program.py file:
from ...src import module
and
from ..src import module
both are giving me:
ValueError: Attempted relative import in non-package

For starters, I recommend reading the entry Modifying Python's Search Path in the docs.
It might be frowned upon by some, but if you wish to modify the PYTHONPATH from within your program, according to the documentation's standard modules entry you can use the sys.path.append method:
import sys
sys.path.append('..')
import module

Couldn't you use PEP 328 to solve this?

If you run program.py directly, with python program.py or with #!, then module.py's directory should be in the PYTHONPATH for import module to work. This can be achieved using a helper shell script that's kept in programDir, for instance, and looks something like:
#!/bin/bash
script_dir=`dirname $0`
# Add the script's parent directory to the PYTHONPATH
export PYTHONPATH=$PYTHONPATH:$script_dir/..
python $script_dir/program.py
Another, probably better, way would be to have program.py export a "main()" function, and create a helper python script at src/program that looks like:
#!/usr/bin/env python
from programDir.program import main
main()
In this case, you can use relative imports in src/programDir/program.py, so this should work:
from .. import module

The first one worked because Python's sys.path's first entry is '' which means it will look for module names in the current working directory from which you've executed the Python interpreter.
The issue you seem to have is that the directory located at src is not set on your PYTHONPATH. So, you can do is set the PYTHONPATH environment variable explicitly.
Here's an example using bash:
export PYTHONPATH=PATH_TO_SRC:${PYTHONPATH}
then run your program as normal
Another approach is that you can explicitly set sys.path by appending to it upon execution of your program.
So, in your program.py, you would have:
if __name__ == '__main__':
import os
import sys
sys.path.append(os.path.dirname(os.path.dirname(__file__)))
your_main_function()
Lastly, for serious python development, you should consider virtualenv and virtualenvwrapper as it will take care of most of these things for you.

You need to add __init__.py to /programDir to interpret the directory as a package. Once a package, you can import the package's contents.
So, in your case, if /src is on the PYTHONPATH, from module.py you can import program.py with from programDir import program.

If you use program as part of a package, in another python module, such as
import src.programDir.program as p
p.some_method()
you can use relative import in program.py, assuming you are creating a package with src (__init__.py in both src and programDir)
from .. import module
If not, for example you are calling program.py from the command line, you must add the directory containing src to your search path either by modifying sys.path or the PYTHONPATH env var, before importing.