Develop Reference

Why pytest can't import tinydb module?

I'm working through the "Python Testing with Pytest" book.
I'm importing tinydb module to run assertions against it and terminal is giving
me error:
test_add_variety.py:1: in <module>
import pytest, tasks, tinydb
E ModuleNotFoundError: No module named 'tinydb'
however it is installed:
pip3 freeze:
click==7.1.2
six==1.16.0
tasks==0.1.0
tinydb==3.15.1
and I can also confirm by firing up Python interpreter:
(venv) mark#fid:~/p_test/ch2$ python
Python 3.8.10 (default, Sep 28 2021, 16:10:42)
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tinydb
>>>
Please note that I'm running these with virtual environment activated.
Any suggestions why Pytest can't import tinydb module ?

ModuleNotFoundError: No module named 'psycopg2' (python3, mac, pip3 shows psycopg2 successfully installed)

Solved: Learn about virtual environments.
pip install virtualenv
Problem: I get a ModuleNotFoundError for psycopg2 in python3, though it's successfully installed via pip3. (I posted short code to summarize from the terminal, but the errors are of course bugging me with .py scripts I'm trying to run.)
Python3 packages:
macs-MacBook-Air-2% pip3 list
Package Version
---------- -------
pip 19.2.3
psycopg2 2.8.4
setuptools 41.4.0
wheel 0.33.6
Python3 psycopg2 error:
macs-MacBook-Air-2% python3
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 16:52:21)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import psycopg2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'psycopg2'
I've only done:
pip3 install psycopg2
Extra notes:
As a side note, everything works fine when I run 2.7. (I used pip install psycopg2.)
macs-MacBook-Air-2% python
Python 2.7.10 (default, Oct 6 2017, 22:29:07)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import psycopg2
>>> psycopg2.__version__
'2.8.4 (dt dec pq3 ext lo64)'
>>>
python 2.7 packages:
macs-MacBook-Air-2% pip list
DEPRECATION: ...2.7 end of life notice..
Package Version
-------------------------------------- -----------
altgraph 0.10.2
astroid 1.6.6
...more
psycopg2 2.8.4
...more
zope.interface 4.6.0
I'm very new to coding, and I searched this error. But, I did not find results that made sense to me including both a python3 error + successful python3 installation.

This could be because your default python installation is Python 2. I think you should create a virtual environment and the install psycopg2 on it. This way you will use pip3 and have isolated dependencies that won't generate conflicts with other versions (and maybe corrupt your system):
python3 -m venv ~/.environments/test
source ~/.environments/test/bin/activate
pip install psycopg2

Python 2.7 modules don't exists

Where can I find modules 'builtins' and 'future.backports.html'? I need these modules to run program at https://github.com/folz/cleverbot.py/blob/master/cleverbot/cleverbot.py
I tried to install these modules by 'pip' in cmd but cmd says that these modules don't exists.

In the setup.py it says:
install_requires=['future', 'requests'],
So I would imagine that pip install future should do the trick:
$ pip install future
Downloading/unpacking future
Downloading future-0.15.2.tar.gz (1.6MB): 1.6MB downloaded
Running setup.py (path:/tmp/pip-build-Q_wkRy/future/setup.py) egg_info for package future
[..]
Successfully installed future
Cleaning up...
$ python
Python 2.7.10 (default, Oct 14 2015, 16:09:02)
[GCC 5.2.1 20151010] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from builtins import str
>>> from future.backports.html import parser
Not sure why you're not just running the setup.py file or using pip?

How to solve importing python packages " No module named "?

I am coming across a strange problem, I already installed python packages but it doesn't recognize them. please note that some packages are recognizable.
An example of importing a package
ActivePython 2.7.5.6 (ActiveState Software Inc.) based on
Python 2.7.5 (default, Sep 16 2013, 23:07:15)
[GCC 4.2.1 (Apple Inc. build 5664)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import requests
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named requests
Whenever I try to install it using Pip like
sudo pip install requests
I got this message whenever I try to install the same package.
Requirement already satisfied (use --upgrade to upgrade): requests in /usr/local/lib/python2.7/site-packages
What should I do to solve this problem ?
UPDATE_1
pip --version
pip 7.1.2 from /usr/local/lib/python2.7/site-packages

Find where pip installs your package and add the path to
export PYTHONPATH=<path>
#my path was /Library/Python/2.7/site-packages
in your .bashrc or .profile file.

Wrong Django version returned in virtualenv

I'm on a Mac running OS X !0.10 Yosemite. Default versions of Python & Django are 2.7 & 1.5. I'm want to set up a virtualenv that has Django 1.8 so I'm doing the following:
$ virtualenv --no-site-packages django18env
New python executable in django18env/bin/python2.7
Also creating executable in django18env/bin/python
Installing setuptools, pip...done.
$ source django18env/bin/activate
(django18env)$
Then I'm installing Django 1.8
(django18env)$ sudo pip install django==1.8
Password:
Downloading/unpacking django==1.8
Downloading Django-1.8-py2.py3-none-any.whl (6.2MB): 6.2MB downloaded
Installing collected packages: django
Successfully installed django
Cleaning up...
(django18env)$
Once that has run I have Django installed under django18env/lib/python2.7/site-packages/django
If I look at the __init__.py file in that directory it shows:
from django.utils.version import get_version
VERSION = (1, 8, 0, 'final', 0)
So it certainly looks like the right version is installed in the virtualenv directory. However, if I use django-admin --version I get:
(django18env)$ django-admin version
1.5.4
I've also tried starting python in the virtual env and getting the django version that way:
(django18env)$ python
Python 2.7.8 (default, Jul 29 2014, 21:50:48)
[GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import django
>>> django.get_version()
'1.5.4'
>>>
Any ideas on why it still seems to be pointing to 1.5 when 1.8 is installed in the vertualenv?
I've read various other threads on here but can't get the version to point to 1.8
Any help much appreciated
Thanks

don't use sudo on virtualenv. the point of vitualenv is, to install software not system wide, but verily for that enviroment. but no matter inside a virtualenv or outside it, if you use sudo, it will install software to your system globally.
ziya#ziya:~/Desktop/coursera/python/lorem$ virtualenv ipsum
New python executable in ipsum/bin/python2.6
Also creating executable in ipsum/bin/python
Installing setuptools, pip...done.
#created a virtualenv
ziya#ziya:~/Desktop/coursera/python/lorem$ cd ipsum/
ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ . bin/activate
# will now install package with sudo
(ipsum)ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ sudo pip install sudokulib # i don't know what it is, just installing.
[sudo] password for ziya:
.....
Collecting sudokulib
/usr/local/lib/python2.7/dist-packages # attention to this path!
...
Successfully installed sudokulib-0.6a0
(ipsum)ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ python
Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sudokulib # import the newly installed module
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named sudokulib
>>> exit()
(ipsum)ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ deactivate
#deactivating virtualenv and starting default python
ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ python
Python 2.7.3 (default, Dec 18 2014, 19:10:20)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sudokulib
>>> sudokulib.__version__
'0.6a' #here it is!
>>> exit()
ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ . bin/activate
(ipsum)ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ pip install sudokulib #now installing the same module without sudo
Collecting sudokulib
Downloading sudokulib-0.6a.tar.gz
/home/ziya/Desktop/coursera/python/lorem/ipsum/lib/python2.6/site-packages
....
Successfully installed sudokulib-0.6a0
(ipsum)ziya#ziya:~/Desktop/coursera/python/lorem/ipsum$ python
Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sudokulib
>>> sudokulib.__version__
'0.6a' #seems ok now :)
>>>

I found the issue. As I say above, Django 1.8 was being installed in the virtualenv OK but Python wasn't using it. In the vitualenv I started Python and then:
>>>import django
>>>django.__file__
This showed that Django had been imported from:
/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages
And when I looked in my .bash_profile there was a line:
export PYTHONPATH=$PYTHONPATH:/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages
Not sure how/when this got in there but I commented it out, restarted the shell and I now get Django1.8 in my virtualenv and the older (default) version 1.5 outside the virtualenv.
Thanks for the help and suggestions