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Modules Not Found - I cannot externally run a .py file developed using PyCharm

I am using PyCharm to develop a python project, which uses an external library called win10toast. I have installed win10toast using PyCharm. However, when I tried to run the .py file using cmd (i.e Externally running the python file), an error shows up:
ModuleNotFoundError: No module named 'win10toast'.
I have python 3.6.4. I installed win10toast using PyCharm.
from win10toast import ToastNotifier
I expect the program to run without any error, but currently I am getting the ModuleNotFound error.

Python can be tricky to run properly because it is sensitive to where you installed your dependencies (such as external libraries and packages). If you installed Python to one directory, but accidentally installed the external library to another directory, when you run your .py program, it will be unable to call from the external library because it doesn't exist in the same library that Python is running from.
Lookup where you installed Python on your computer and then find where you installed the external library. Once your find where you installed the external library, move its entire package content to the same directory where Python is installed. Or better yet, reinstall the external library with pip into the same directory as Python.
If you're on Mac, Python and its related dependencies are usually stored somewhere in /User/bin. If you're on Windows, it will be stored somewhere in your C:// directory (possibly somewhere in C:\Users\username\Local\AppData). If you're on Linux, it will be stored somewhere in /usr/bin. Whatever you do, don't move Python from wherever it is because sometimes that can mess up your system for certain operating systems like Mac, which comes with its own version of Python (Python 2.7 I believe, which is outdated anyway).
Lastly, you may have two different versions of Python on your computer, which is common; Python 2.7 and Python 3+. If you wrote your program in one version, but ran it from the other, the external library can only be called from whichever Python version you installed it to. Try running your .py program with python3 instead of python (or vice versa) and see what happens. If it works with one python version over the other, that tells you that the external library is installed in the other version's directory.
That should solve your issue.

I would suggest that you not use PyCharm to install packages, at least not
if the result deviates in the slightest from doing a "pip install" at the command line. I see no reason to involve PyCharm in configuring Python installations. It's just asking for trouble.
I admit that I'm not familiar with the practice I'm suggesting you avoid. I've been using PyCharm since pretty much the week it came out (was an avid user of the IntelliJ Python plugin before that), and have never once considered doing anything but installing Python modules at the command line. That way, I'm sure right where those modules are going (into which base Python install or venv). Also, I know I'm doing all that I can to minimize the differences that I might see between running code in PyCharm and running it at the command line. I'm making my suggestion based solely on this practice having never gone wrong for me.
I have multiple base Python versions installed, and dozens of venvs defined on top of those. PyCharm is great at allowing me to indicate which of these I want to apply to any project or Run/Debug configuration, and utilizing them seamlessly. But agin, I administer these environments at the command line exclusively.
I still experience issues in switching between the command line and PyCharm in terms of one module referencing others in a single source tree. My company has come up with a simple solution to this that insures that all of our Python scripts still run when moving away from PyCharm and its logic for maintaining the Python Path within a project. I've explained the mechanism before on S.O. I'd be happy to find that if anyone is interested.

The library win10toast installed in the directory: YOUR_PYCHARM_WORKSPACE\PycharmProjects\YOUR_PROJECT_NAME\venv\Lib\site-packages
but when you are running your program using cmd, pycharm interpreter uses site-packages directory that you installed python at there. for Ex: C:\Python27\Lib\site-packages
So, you can install the win10toast library to this windows directory using pip.

How to make macports python use its own packages over another installation's?

I have spent days struggling to get a scientific Python environment running on Mac OS Lion. I tried the SciPack Superpack route, and also various manual installations via pip and easy_install, but still got errors trying to import or use various modules. Based on the advice in this Stackoverflow thread I set up a fresh installation using MacPorts.
However, when I run the macports Python, it is ignoring packages in the macports installation and instead trying to load incompatible packages from the old installation. I am absolutely sure that I am running the newly installed macports Python. I have checked the symlinks and have checked python_select and have launched Python by directly typing the path to the new installation. But when I try to import, say, statsmodels, it pulls in the old version from another directory.
Here are the contents of sys.path (edited for brevity):
['',
'/Library/Python/2.7/site-packages/mrjob-0.4.3_dev-py2.7.egg',
'/Library/Python/2.7/site-packages/statsmodels-0.6.0-py2.7-macosx-10.9-intel.egg',
...
'/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python',
'/Library/Python/2.7/site-packages/twilio-3.6.6-py2.7.egg',
'/Library/Python/2.7/site-packages/six-1.6.1-py2.7.egg',
'/Library/Python/2.7/site-packages/httplib2-0.9-py2.7.egg',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python27.zip',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/readline',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/PyObjC',
'/Library/Python/2.7/site-packages']
The macports installation is in /opt/local, while the older installation is under /Library/Python. As you can see, the older packages are higher up in the list, which means that they have higher priority.
Environmental variable PYTHONPATH is empty. If I do put anything into PYTHONPATH, that appears in sys.path after the /Library entries but before the /opt entries. So it does not solve the problem.
If I invoke the new python with the -S option, sys.path becomes:
['',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python27.zip',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload']
That succeeds in getting rid of the alien site packages entries, but it also nukes macports' site-packages entries so then I can't load anything.
I believe that the culprit is a file called /Library/Python/2.7/site-packages/easy-install.pth , with the following contents (again edited for brevity):
import sys; sys.__plen = len(sys.path)
./mrjob-0.4.3_dev-py2.7.egg
...
./statsmodels-0.6.0-py2.7-macosx-10.9-intel.egg
...
/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
./twilio-3.6.6-py2.7.egg
./six-1.6.1-py2.7.egg
./httplib2-0.9-py2.7.egg
import sys; new=sys.path[sys.__plen:]; del sys.path[sys.__plen:]; p=getattr(sys,'__egginsert',0); sys.path[p:p]=new; sys.__egginsert = p+len(new)
If I rename that file before launching macports python, python no longer is adding these alien packages to its sys.path. Now sys.path looks a lot like it does when I use "python -S" option except it has these additional entries at the end:
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages',
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/PyObjC',
'/Library/Python/2.7/site-packages'
Now I am able to load macports' own packages, say for example statsmodels. By checking statsmodels.__file__ I have confirmed that it is importing the local package and not the alien package.
However, I consider this a workaround/kludge rather than a real solution. A solution should make it behave as expected, which is: Macports' Python, launched from /opt/local/... installation, should prioritize packages installed via macports into the /opt/local/... directory tree and go looking elsewhere only if the module does not exist locally. So for example I would expect the /opt/local entries to come first in sys.path, with the /Library entries further down the list.
It seems like this should be the default behavior and I've seen a lot of comments here on Stackoverflow that just assert that this is how Macports Python behaves. So...how do I make it so?

There are at least two separate root causes for the problem you are seeing. One is that non-system OS X framework builds of Python 2.7, including MacPorts Python 2.7, deliberately include the system Python site-packages location, /Library/Python/2.7/site-packages, in sys.path, normally at the end of sys.path after that instance's own site-packages directory. This has been a debated feature in upstream Python and there is an open MacPorts issue to remove it (https://trac.macports.org/ticket/34763), the argument being that it is better to keep the system Python and the MacPorts Python totally separate.
The second root cause is the behavior of the original setuptools package and its easy_install command as supplied with OS X. As you have discovered, it does some fancy manipulation of sys.path by some magic tricks with .pth files, including easy-install.pth, to ensure that the packages that have been installed using easy_install show up first in sys.path and override other installed versions of those packages. Also as you have found, one way - and the easiest way - to remove that behavior is to delete the easy-install.pth file in /Library/Python/2.7/site-packages. That is assuming you don't want to use any of the packages installed there with the Apple-supplied system Python.
The long-term strategy to avoid this problem in the future is to make sure you do not use the Apple-supplied easy_install or easy_install-2.7 commands found in /usr/bin. They will install packages to /Library/Python for use by the system Python and will create or update easy-install.pth. In general, you should avoid use of easy_install all together. Its modern replacement is pip which provides better control and avoids tricks with .pth files. If MacPorts doesn't already provide a port for the Python package you want to install, usually of the form py27-xxxx, install and use the MacPorts py27-pip port instead of easy_install:
/opt/local/bin/pip-2.7 install xxxx
You can also use the usual MacPorts features like port select pip pip27.

How to install Python in Linux without previous version installed

I'm currently doing some embedded systems programming. This was set up by somebody else a few years ago. So now I'm looking to upgrade to Python 2.7.2 to make things simpler because I have already run into two cases where what I coded wasn't supported.
What is currently running:
: uname -a
Linux host1 2.6.18-6-486 #1 Sun Feb 10 22:06:33 UTC 2008 i586 GNU/Linux
: python -v
Python 2.4.4
: pyversions -i
python2.4
So right now only 2.4 is installed.
I untarred python2.7.2 and when I go to that directory and run python27 setup.py install --home=/home/jhemilian and it seems like python2.4 doesn't seem to know the with...as statement syntax:
host1:/home/jhemilian/src/Python-2.7.2: python setup.py install --home=/home/jhe
milian
File "setup.py", line 361
with open(tmpfile) as fp:
^
SyntaxError: invalid syntax
Before I go figuring this out I first have a question: python itself is being used to install Python? What if I didn't have the first version of Python installed? I know it's shipped with most Linux but hypothetically -- how does such a seeming catch-22 like that work?
What I am looking to do is install python2.7 in a benign location, keeping the python command still as using Python 2.4 just in case the "legacy" software i'm running is dependent on it, and running python2.7 myscript.py et cetera when I want to run one of my newer scripts. Feel free to comment if there is a cleaner or more practical (or even safer!) way to do this.
I don't think it would make much sense to go replacing all the with statements with compatible try blocks. I've looked though the READMEs and online documentation but I can't seem to find a way to install Python without already having Python. Note that I DO NOT have internet connection, although if desirable or necessary I could. It would be great if somebody could point me in the right direction. Thanks!!

It's all right in the README...
You don't need to use python to install, in fact, you shouldn't...just:
./configure
make
make install
If you want to install in a specific dir, just follow what the README says:
Installing
To install the Python binary, library modules, shared library modules
(see below), include files, configuration files, and the manual page,
just type
make install
This will install all platform-independent files in subdirectories of
the directory given with the --prefix option to configure or to the
prefix' Make variable (default /usr/local). All binary and other
platform-specific files will be installed in subdirectories if the
directory given by --exec-prefix or theexec_prefix' Make variable
(defaults to the --prefix directory) is given.
If DESTDIR is set, it will be taken as the root directory of the
installation, and files will be installed into $(DESTDIR)$(prefix),
$(DESTDIR)$(exec_prefix), etc.
All subdirectories created will have Python's version number in their
name, e.g. the library modules are installed in
"/usr/local/lib/python/" by default, where is the
. release number (e.g. "2.1"). The Python binary is
installed as "python" and a hard link named "python" is
created. The only file not installed with a version number in its
name is the manual page, installed as "/usr/local/man/man1/python.1"
by default.
If you want to install multiple versions of Python see the section
below entitled "Installing multiple versions".
The only thing you may have to install manually is the Python mode for
Emacs found in Misc/python-mode.el. (But then again, more recent
versions of Emacs may already have it.) Follow the instructions that
came with Emacs for installation of site-specific files.

EDIT: virtualenv is apparently for already-installed Python versions. Disregard this recommendation.
I think what you want is virtualenv.
I haven't used it myself, but I understand this is what it's meant for.
From the website:
virtualenv is a tool to create isolated Python environments.
The basic problem being addressed is one of dependencies and versions, and indirectly permissions. Imagine you have an application that needs version 1 of LibFoo, but another application requires version 2. How can you use both these applications? If you install everything into /usr/lib/python2.7/site-packages (or whatever your platform's standard location is), it's easy to end up in a situation where you unintentionally upgrade an application that shouldn't be upgraded.
EDIT: Upon review, I think you want Alberto's answer, so I voted him up for visibility.

zlib module missing - python 2.4.3

I am trying to get simplejson installed on this python 2.4.3 - I cannot upgrade, I know it is old, there is nothing I can do about it, it is not my fault, please help. however when i do the ..\python.exe .\setup.py install i get:
File "C:\Program Files (x86)\WorldViz\Vizard30\bin\lib\zipfile.py", line 188, in __init__ raise RuntimeError,\
RuntimeError: Compression requires the (missing) zlib module
Does anyone know how can I get zlib installed on this windows 64 machine? or where I can get a compiled version of simplejson or where can I find a compatible alternative for it.
Again, I can't do anything about it being python 2.4.3 - it is a proprietary modified version of python that I cannot do a thing about.

Copying the .py files into site-packages will get some stuff to work - particularly you can read files from an uncompressed zip archive, but you will not be able to inflate compressed files. The problem you are having is that ./config is not finding zlib.so (or possibly zlib.h) where it expects to find it and skips making it. This is a problem in compiling old versions of Python (pre 2.6) on recent Ubuntu boxes (Natty Narwhal - 11.0 in particular) since Canonical restructured the /lib directory contents to better (for them) support multiple architectures. So config is looking for the file /lib/libz.so and it is in /usr/lib/i386-linux-gnu/libz.so (or some other /usr/lib/$ARCH/ directory depending upon your machine).
It is supposed to be possible to tell config additional directories to search by exporting shell variables. I couldn't get that to work. What did work was the nasty hack
ln -s /usr/lib/i386-linux-gnu/libz.so /lib/libz.so
There are other parts of the standard library that config considers optional that are affected by this, but I didn't have time to track them down. After you do "make" do a "make test" and at the end it will list which packages were expected on Linux that it did not find.

The zlib module comes in the Standard Library, and I do not see a separately installable version on the Python Package Index. It is actually integral to Python, since Python cannot run its own Standard Library without it if the library is distributed as a ZIP file, so this must be a very customized Python if it lacks it. Could you build normal Python from source in another directory and in the presence of the library files for zlib, and then copy the zlib.so file over to see if it will link against this crazy Python you are using?
Edit: And, come to think of it, why do you need a compiled version of simplejson? Is the plain Python version not enough?
Edit: Here is how I can install simplejson without trying to get its accelerator routine to compile:
$ wget http://pypi.python.org/packages/source/s/simplejson/simplejson-2.1.1.tar.gz
$ tar xvfz simplejson-2.1.1.tar.gz
$ cd simplejson-2.1.1
$ cp -r simplejson /usr/lib/python2.4/site-packages
Those first three steps can all occur on some other system, and of course you can just use your web browser rather than wget. But the point is that you can just copy the whole simplejson directory from inside of the .tar.gz into your site-packages and it should work. It's a messy way to manually install, but it sure won't depend on any other dependencies! :-)

Python MySQL and Django problem

I am having problems getting python/django to connect to a MySQL database. The error message is basically "Error Loading MySQLDb module: No module named MySQLDb".
This is a fresh install right off python.org, so I assumed that it would have the MySQLDb module included, but it does not seem to. I also can't seem to find the module or how to install it, except in some sleazy looking parts of the net.
Is there a central point for getting this module? Why isn't it in the standard install? Can someone point me to a tutorial or some such to get this module installed?
Newbie in python, MySQL and Django.
Thanks for help.

I believe http://pypi.python.org/pypi/MySQL-python/ is the Python module you need. In general, when looking for Python modules, http://pypi.python.org/ is where you should start (people will refer to it as either PyPI or "the cheese shop." If setuptools is installed (it may be already) then you can run easy_install MySQL-python.
As far as MySQL is concerned, you'll need to install that separately from a likely-looking package on http://dev.mysql.com/downloads/mysql/.

this is how i handled the issue on Fedora13:
you can get the module here: http://sourceforge.net/projects/mysql-python/
download to a convenient directory
read the README file
build the module, according to the instructions in the README, keeping in mind to use the version of python you are planning to use as an interpreter (2.6 for me). if there are more than one version of python, simply using 'python' will probably alias you into a particular version, which might not be the one you want.
after the build is complete, the .egg file will have been created and landed in a 'site-packages' directory associated with the version of python which was used for the build.
then, ensure that the .egg file created (you can see the install path in the output from the install) is placed on your PYTHONPATH
that did it for me, anyhoo...
good luck!
JR