Develop Reference

No module named 'psutil', although it is installed (MacOS)

When I run my code that includes psutil module I encounter the following error:
Traceback (most recent call last):
File "/Users/alek/Desktop/coloring/solver.py", line 4, in <module>
from psutil import cpu_count
ModuleNotFoundError: No module named 'psutil'
Although, when trying to install the module in terminal, I can see the following
DEPRECATION: Configuring installation scheme with distutils config files is deprecated and will no longer work in the near future. If you are using a Homebrew or Linuxbrew Python, please see discussion at https://github.com/Homebrew/homebrew-core/issues/76621
Requirement already satisfied: psutil in /opt/homebrew/lib/python3.9/site-packages (5.9.1)
DEPRECATION: Configuring installation scheme with distutils config files is deprecated and will no longer work in the near future. If you are using a Homebrew or Linuxbrew Python, please see discussion at https://github.com/Homebrew/homebrew-core/issues/76621
WARNING: There was an error checking the latest version of pip.
How should I ensure that the module is in the right environment and can be used by my program?
Thanks in advance!

try to upgrade it
sudo pip install --upgrade psutil

try to run this command in python shell:
import site
site.getsitepackages()
actually, it is trying to search psutil module in one of the Xcode path.
see if you have psutil in this path:
/Applications/Xcode_13.4.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/site-packages
if not add the psutil module here and it should work.
it worked for me.

Trying to install libraries in pypy

I knew that pypy is faster than CPython so I wanted to try it and it is actually way faster than CPython, however when I install libraries it shows the following:
PS C:\Users\DELL\Desktop\telegram\python -work some-> pip install pillow
Requirement already satisfied: pillow in c:\users\dell\appdata\roaming\python\python39\site-
packages (8.3.0)
but when I try to import the module (pillow):
Traceback (most recent call last):
File "c:/Users/DELL/Desktop/telegram/python -work some-/studying code 2.py", line 1, in
<module>
import pillow
ModuleNotFoundError: No module named 'pillow'
it is not there! please help!

pillow is an up-to-date fork of the now deprecated Python Image Library (PIL). you need to import PIL or from PIL import ... to use it.
Check out their documentation to learn more!

You must run pip with the version of Python you want to install the package for. In this case, you need pypy3 -m pip install pillow or something similar---run it with the same interpreter as the script you'll run next. In your pasted output, we see Requirement already satisfied: pillow in c:\users\dell\appdata\roaming\python\python39\site-packages which is the path for CPython 3.9, not PyPy.

How can i install python modules that have spaces in between?

I wanted to run a script that would scan my network and that script uses a awesome library called who-is-on-my-wifi. I have installed the module to run the script but i get errors from the prompt saying that it cannot detect such a module in the system.
This is the script.
from who_is_on_my_wifi import *
WHO = who()
for i in range(0, len(WHO)):
print(WHO[i])
And this is the error that i get.
python scanner.py
Traceback (most recent call last):
File "scanner.py", line 1, in <module>
from who_is_on_my_wifi import *
ImportError: No module named who_is_on_my_wifi
This is the proof that i have installed the module
pip3 install 'who_is_on_my_wifi'
Requirement already satisfied: who_is_on_my_wifi in /home/harein/.local/lib/python3.8/site-packages (1.2.0)
Requirement already satisfied: getmac in /home/harein/.local/lib/python3.8/site-packages (from who_is_on_my_wifi) (0.8.2)
Requirement already satisfied: python-nmap in /home/harein/.local/lib/python3.8/site-packages (from who_is_on_my_wifi) (0.6.1)
Any suggestions on how i can avoid this can continue executing my script ?
EDIT
The script finally executed the way i want by changing the,
python scanner.py to python3 scanner.py
You guys were right, it was the way how i executed the script that generated this error and it was not a problem in the module apparently.
I would like to thank everyone who gave the support.<3

When trying to
import this_is_not_a_module
the error you get:
ImportError: No module named this_is_not_a_module
is the error raised by Python 2.
Python 3 would raise a different one:
ModuleNotFoundError: No module named 'this_is_not_a_module'
So, your actual problem is that your system tries to execute your script with some Python 2 version, while you installed your module for your Python 3.8 version.

sometimes you can't import modules because you have installed two python versions(or conda along with it). if you have, delete one of your python versions or activate conda and try importing your module, or just try:
pip uninstall who_is_on_my_wifi
pip install who_is_on_my_wifi

I usually tend to install modules per project and use virtualenv for it.
It kind of links respective versions of programs (like python interpreter, pip and so on) and takes care of PYTHONPATH and the way of installed dependencies.
$ pip3 install virtualenv
$ virtualenv whoisonwifi
$ source whoisonwifi/bin/activate
$ pip --version
pip 21.0.1 from
/mnt/devel/workonhome/whoisonwifi/lib/python3.7/site-packages/pip
(python 3.7)
$ pip install 'who_is_on_my_wifi'
from there your code (sort of) works for me.

How should I handle importing third-party libraries within my setup.py script?

I'm developing a Python application and in the process of branching off a release. I've got a PyPI server set up on a company server and I've copied a source distribution of my package onto it.
I checked that the package was being hosted on the server and then tried installing it on my local development machine. I ended up with this output:
$ pip3 install --trusted-host 172.16.1.92 -i http://172.16.1.92:5001/simple/ <my-package>
Collecting <my-package>
Downloading http://172.16.1.92:5001/packages/<my-package>-0.2.0.zip
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\<me>\AppData\Local\Temp\pip-build-ubb3jkpr\<my-package>\setup.py", line 9, in <module>
import appdirs
ModuleNotFoundError: No module named 'appdirs'
----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in C:\Users\<me>\AppData\Local\Temp\pip-build-ubb3jkpr\<my-package>\
The reason is that I'm trying to import a third-party library appdirs in my setup.py, which is necessary for me to compute the data_files argument to setup():
try:
from setuptools import setup
except ImportError:
from distutils.core import setup
import os
from collections import defaultdict
import appdirs
from <my-package>.version import __version__ as <my-package>_version
APP_NAME = '<my-app>'
APP_AUTHOR = '<company>'
SYSTEM_COMPONENT_PLUGIN_DIR = os.path.join(appdirs.user_data_dir(APP_NAME, APP_AUTHOR), 'components')
# ...
setup(
# ...
data_files=component_files,
)
However, I don't have appdirs installed on my local dev machine and I don't expect the end users to have it either.
Is it acceptable to rely on third-party libraries like this in setup.py, and if so what is the recommended approach to using them? Is there a way I can ensure appdirs gets installed before it's imported in setup.py, or should I just document that appdirs is a required package to install my package?

I'm ignoring licensing issues in this answer. You definetly need to take these into account before you really do a release.
Is it acceptable to rely on third-party libraries like this in setup.py
Yes, it is acceptable but generally these should be minimized, especially if these are modules which have no obvious use for the end-user. Noone likes to have packages they don't need or use.
what is the recommended approach to using them?
There are basically 3 options:
Bootstrap them (for example use pip to programmatically install packages). For example setuptools provides an ez_setup.py file that can be used to bootstrap setuptools. Maybe that can be customized to download and install appdirs.
Include them (especially if it's a small package) in your project. For example appdirs is basically just a single file module. Pretty easy to copy and maintain in your project. Be very careful with licensing issues when you do that!
Fail gracefully when it's not possible to import them and let the user install them. For example:
try:
import appdirs
except ImportError:
raise ImportError('this package requires "appdirs" to be installed. '
'Install it first: "pip install appdirs".')

You could use pip to install the package programmatically if the import fails:
try:
import appdirs
except ImportError:
import pip
pip.main(['install', 'appdirs'])
import appdirs
In some circumstances you may need to use importlib or __import__ to import the package after pip.main or referesh the PATH variable. It could also be worthwhile to include a verification if the user really wants to install that package before installing it.
I used a lot of the examples from "Installing python module within code" and I haven't personally tried used this in setup.py files but it looks like it could be a solution for your question.

You can mention install_requires with the dependencies list. Please check the python packaging guide here. Also you can provide a requirements.txt file so that it can be run at once using "pip install -r"

setuptools easyinstall mysql-python-1.2.3

I have read a bunch of threads on setuptools here.
A lot of people seem not to like it very much.
But I need to install MySQL-python-1.2.3. and when I do that I get this error:
MySQL-python-1.2.3 X$ python setup.py cleanTraceback (most recent call last):
File "setup.py", line 5, in <module>
from setuptools import setup, Extension
ImportError: No module named setuptools
So it seems I need setuptools and that it is assumed that it is installed.
On the setuptools python homepage it says:
Setuptools will install itself using the matching version of Python (e.g. python2.4), and will place the easy_install executable in the default location for installing Python scripts (as determined by the standard distutils configuration files, or by the Python installation).
Does this mean it will replace any default easy install from python?
If so I dont want to use it.
If so can I install MySQL-python-1.2.3 without setupttools?
Thanks

You should use virtualenv and pip.
Virtualenv automatically creates a setuptools version within the new environment, so the default one is intact.
You may want to read how the packaging and installing works: 1, 2