Develop Reference

Upgrade python to 3.10 in windows; Do I have to reinstall all site-packages manually?

I have in windows 10 64 bit installed python 3.9 with site-packages. I would like to install python 3.10.2 on windows 10 64 bit and find a way to install packages automatically in python 3.10.2, the same ones I currently have installed in python 3.9. I am also interested in the answer to this question for windows 11 64 bit.

I upgraded to python 3.10.2 in windows 10 64 bit. To properly install the packages, install the appropriate version of the Microsoft Visual C++ compiler if necessary. Details can be read https://wiki.python.org/moin/WindowsCompilers . With the upgrade to python 3.10.2 from 3.9, it turned out that I had to do it, due to errors that are appearing during the installation of the packages. Before the installing python 3.10.2, type and execute the following command in the windows command prompt:
pip freeze > reqs.txt
This command writes to the reqs.txt file the names of all installed packages in the version suitable for pip. If you run the command prompt with administrator privileges, the reqs.txt file will be saved in the directory C:\WINDOWS\system32.
Then, after the installing of python 3.10.2 and the adding it to the paths in PATH, with the help of the command prompt you need to issue the command:
pip install -r reqs.txt
This will start the installing of the packages in the same versions as for python 3.9. If problems occur, e.g. an installation error appears during the installation of lxml, then you can remove from the regs.txt file the entry with the name of the package whose installation is causing the problem and then install it manually. To edit the reqs.txt file you need the administrator privileges. The easiest way is to run the command prompt in the administrator mode, type reqs.txt and click Enter to edit it.
I decided later to update the missing packages to the latest version, because I suspected that with python 3.10.2 older versions were not compatible.
This means that when upgrading to python 3.10.2 it is worth asking yourself whether it is better to upgrade for all packages. To do this, you can generate the list of the outdated packages using the command:
pip list –-outdated
After the printing of the list in the command prompt, you can upgrade the outdated packages using the command:
pip install --upgrade <package-name>
This can be automated by the editing of the reqs.txt file and the changing of the mark == to > which will speed up the upgrade. The mark > should only be changed for the outdated packages or you will get an error: "Could not find a version that satisfies the requirement ... ".
Supplement to virtual environments:
When you enter a virtual environment directory (in the windows command prompt):, such as D:\python_projects\data_visualization\env\Scripts, type activate to activate it. Then create the reqs.txt file analogous to the description above. Then, copy the file to a temporary directory. After this delete the virtual environment, e.g. using the windows explorator by the deleting of the contents of the env directory. Then, using the version of python in windows of our choice, create a virtual environment using the env directory (see: https://docs.python.org/3/library/venv.html). Copy the regs.txt file to the newly created D:\python_projects\data_visualization\env\Scripts directory. Install site-packages with the support of the regs.txt file as described above.

No you need not reinstall python packages.
conda create --name project-env python=3.x
You can also look at an alternative method to install python versions Install python version

how should i be using python 3.6 and python 3.7 side by side on msys2 and cmder?

I'm using msys2 for my dev environment on Windows 10. It's great, and this is the first roadblock I've come up against.
Specifically I'm trying to install some packages that won't allow me to via pip because my platform is incorrect. They require a 3.6 platform and msys2 comes with 3.7
I tried pyenv-win, but that wouldn't seem to work within cmder and it also installed some full windows installers of python 3.6.
Is there a recommended way to get another version of python installed using the msys ecosystem of command lines?

I know you want to use msys2, but you should reconsider, the majority of implementation don’t use msys2. multiple versions and multiple environments can get complicated. If you choose to go forward in a more standard way, you could use what I have written below
You can’t create a virtual env with a version of python that isn’t install in your system.
Downloaded and install the version of python you want to use, from https://www.python.org/
Create a project folder
Create a venv calling the newly installed version of python
venv is part of the standard library
c:\>python -3.x -m venv c:\path\to\myenv
it created a copy of the python executable in the newly created venv
https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/
Activate the new env
c:\> c:\path\to\myenv\Scripts\activate.bat
(venv) path\to\myenv>
Once activated you can pip install
(venv) path\to\myenv> pip install [package.name]
(venv) path\to\myenv> pip list
Any script you run from that venv will used the python exe installed in that virtual environment and use the packages you just installed there

Pip install in Spyder

I'm using Python 3.6 through Spyder in Anaconda3.
I have both the Anaconda installation and a "clean" python installation.
Before I installed the "clean" python, when I ran the Python -V command in cmd I got the following version description Python 3.6.5 :: Anaconda, Inc. Now when I run the command it just says Python 3.6.5. and the pip list is a whole lot shorter.
When ever I open Spyder and find some package that I don't have... how would I go about installing said package?
If I just open cmd and write pip install ... it will install in the "clean" python directory.
How do I tell it to connect to Spyder?

I know it's a very late answer, but it may help other people.
When you are working with anaconda you can use the basic environement or create a new one (it may be what's you call a "clean" python installation). To do that just do the following :
Open you anaconda navigator
Go to "Environments"
Click on the button create. Here by the way you can choose you python version
Then to install your lib you can use your Anaconda GUI :
Double click on you environment
On the right side you have all you installed lib. In the list box select "Not installed"
Look for your lib, check it and click on "apply" on the bottom right
You can also do it in your windows console (cmd), I prefer this way (more trust and you can see what's going on) :
Open you console
conda activate yourEnvName
conda install -n yourEnvName yourLib
Only if your conda install did not find your lib do pip install yourLib
At the end conda deactivate
/!\ If you are using this way, close your Anaconda GUI while you are doing this
If you want you can find your environement(s) in (on Windows) C:\Users\XxUserNamexX\AppData\Local\Continuum\anaconda3\envs. Each folder will contains the library for the named environement.
Hope it will be helpfull
PS : Note that it is important to launch spyder through the Anaconda GUI if you want Spyder to find your lib

If you are using Spyder IDE easiest procedure which i found to install PIP is -:
Step 1- Check if Python is installed correctly.
The simplest way to test for a Python installation on your Windows server is to open a command prompt (click on the Windows icon and type cmd, then click on the command prompt icon). Once a command prompt window opens, type python and press Enter. If Python is installed correctly, you should see output similar to what is shown below:
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
Step 2-: Now in Step 2
Once you’ve confirmed that Python is correctly installed, you can proceed with installing Pip.
Download get-pip.py
https://bootstrap.pypa.io/get-pip.py
to a folder on your computer.
Open a command prompt and navigate to the folder containing get-pip.py.
Run the following command:
python get-pip.py
Pip is now installed!
You can verify that Pip was installed correctly by opening a command prompt and entering the following command:
pip -V
You should see output similar to the following:
pip 18.0 from c:\users\administrator\appdata\local\programs\python\python37\lib\site-packages\pip (python 3.7)enter code here

There is a pip.exe included in the anaconda/Spyder package which can cleanly add mopdules to Spyder. It's not installed in the windows path by default, probably so it' won't interfere with the "normal" pip in my "normal" python package.
Check "/c/Users/myname/Anaconda3/Scripts/pip.exe". It seems to depend on local DLLs - it did not work (just hung) until I cd'd into it's directory. Once there I used it to install pymongo in the usual way, and the pymongo package was picked up by Spyder.
Hope that helps...

I installed spyder without anaconda on linux, and i was missing a module, all i did was installing pip on the linux terminal
sudo apt install python3-pip and then pip install "the library name "
and it worked in spyder without any other modification.

wxPython: This program needs access to the screen

I'm trying to use the Python GUI wx (installable via pip install wxPython) in the following minimal app:
import wx
app = wx.App()
Running this snippet returns the following:
This program needs access to the screen. Please run with a Framework
build of python, and only when you are logged in on the main display
of your Mac.
Does anyone know how to help wx gain "access to the screen", or what a "Framework build of Python" is? I'd be grateful for any help others can offer with these questions!

wxPython on Mac within a virtual environment throws this error, as explained by wxPython website here: https://wiki.wxpython.org/wxPythonVirtualenvOnMac
If you are not running it in a virtual environment and still receive this error, try running your script that uses wxpython with "pythonw" instead of "python". Ex:
pythonw hello.py
^See section "4.1.2 Running Scripts with a GUI" (on MacOS) from the following page in the Python Docs to see this python quirk explained: https://docs.python.org/3/using/mac.html

This resolves the problem, but it can't be the prettiest solution:
# install anaconda
install anaconda
# uninstall all versions of pythonWx
pip uninstall pythonWx -y
conda remove pythonwx
# install the python.app binary through conda
conda install python.app
# determine where the conda binary lives
which conda
# that previous command returns something like:
# /Users/yaledhlab/anaconda3/bin/conda
# replace the /conda with /python.app
# and run the result in a terminal
/Users/yaledhlab/anaconda3/bin/python.app
# that should open a Python terminal (you know you're in the Python
# terminal if you see >>> as a prefix for your shell)
# import the python package manager and install wxPython to
# your python.app version of Python
import pip
pip.main(['install', 'wxPython'])
# exit the python interpreter
exit()
# run the program
/Users/yaledhlab/anaconda3/bin/python.app main.py

I ran into the same problem. In order to use anaconda's python executable and wxPython on a mac you will need to run "pythonw" (instead of "python"). This calls the python executable that is compatible with wxPython. But in order to get it to work on my mac I had to update my anaconda packages by running:
conda install anaconda #you might not need this if anaconda is up to date
followed by:
conda install wxPython
which installs the "pythonw" executable in the "//anaconda3/bin" directory (you might have anaconda installed somewhere else). Then I could run any "program_with_xwPython.py" that imports/contains and uses wx using "pythonw" as follows:
pythonw program_with_xwPython.py # Note: 'python program_with_xwPython.py' gives the error still, you need to run 'pythonw'
You can then also launch a python REPL (i.e the >>> prompt) that works with wxPython using:
pythonw # instead of 'python'
This let's you import wx and run wx apps with the python CLI. It's been working like a champ for me.

I always had it working, including after update to Catalina and I never needed to run some silly pythonw instead of python and had all my wx-enabled scripts running correctly.
At some time something broke in my environment, I think it was the pip-tools that without any warning started to remove my packages. Not sure what happened but damage has been done and suddenly I saw the infamous
This program needs access to the screen. Please run with a Framework
build of python, and only when you are logged in on the main display
of your Mac.
I manage my environments with pyenv, the current python environment was 3.4.7. Let the script from the question be tst.py, I run
$ python tst.py
This program needs access to the screen. Please run with a
Framework build of python, and only when you are logged in
on the main display of your Mac.
I make sure the wxpython is installed with brew
$ brew info wxpython
wxpython: stable 4.1.1 (bottled)
Python bindings for wxWidgets
https://www.wxpython.org/
/usr/local/Cellar/wxpython/4.1.1 (1,227 files, 91.8MB) *
Poured from bottle on 2021-03-04 at 14:52:18
From: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/wxpython.rb
License: LGPL-2.0-or-later with WxWindows-exception-3.1
==> Dependencies
Required: freetype ✔, jpeg ✔, libpng ✔, libtiff ✔, numpy ✔, python#3.9 ✔
==> Analytics
install: 643 (30 days), 2,701 (90 days), 12,659 (365 days)
install-on-request: 604 (30 days), 2,523 (90 days), 9,914 (365 days)
build-error: 0 (30 days)
The wxPython wiki suggests
The reason is because some 3rd party tools like PyInstaller might require CPython installation be built with --enable-framework. What you need to do is run $ env PYTHON_CONFIGURE_OPTS="--enable-framework" pyenv install 3.x.x in your terminal.
so I re-installed 3.7.4 from scratch
$ pyenv uninstall 3.7.4
$ env PYTHON_CONFIGURE_OPTS="--enable-framework" pyenv install 3.7.4
and tried the script again
$ python tst.py
2021-03-04 15:14:44.138 Python[18815:404240] ApplePersistenceIgnoreState: Existing state will not be touched. New state will be written to (null)
of course it does not completely resolves it but at least the annoying error is gone...

Official wxPython website has a solution:
If you're using conda:
>> conda install python.app # this will install latest pythonw
>> pythonw your_app.py

$ pyenv uninstall 3.9.2
$ env PYTHON_CONFIGURE_OPTS="--enable-framework" pyenv install 3.9.2
Solved the problem for me with my pyenv installation on Mac

#duhaime
There is an installer for OSX on the official wxPython web-site.
Just download it and install.
You don't need to play with anaconda just to install and run such a simple application.

Installation of TensorFlow on windows 7 - 'pip3' is not recognized as an internal or external command,

When following the Installing TensorFlow for Windows guide https://www.tensorflow.org/install/install_windows, after executing
C:\> pip3 install --upgrade tensorflow
I get the following error:
'pip3' is not recognized as an internal or external command,
It looks like pip3 isn't recognized at all (although PATH to python is set)

Run the following
python -m pip install --upgrade tensorflow
Assuming python is working, TensorFlow should get installed (at least the "Validate the installation" step is green).

This will work, if you are facing pip3 or pip is not recognized as an internal or external command issue on windows:
From the desktop, right click the Computer icon.
Choose Properties from the context menu.
Click the Advanced system settings link.
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit.
A new pop up will open. Variable name will remain Path. We will change the Variable value to the location of the folder where your python scripts folder is located. Find it.
For e.g. I changed its value to C:\Users\rgupta6\AppData\Local\Programs\Python\Python35\Scripts
Close all remaining windows. Reopen Command prompt window, and run your pip3 install --upgrade tensorflow command or pip3 install tensorflow command

That is because you haven't setup the environment variable yet.
Follow the steps by #rajesh
I had the same problem and i found his answer helpful
Right click on This PC > Select Properties
Select Advanced system settings on the left
In the dialog box select Environment Variables
In the system variables section select path and cllck on edit
Select new and enter the path where the python scripts are..
it is mostly in C:\Users[your user name]\AppData\Local\Programs\Python\Python36\Scripts
Then ok.. to all the boxes opened
Close cmd if it is already open and now try installing tensorflow using pip again like this
pip3 install --upgrade tensorflow

Before running pip3 install --upgrade tensorflow
you need check if you are using the correct Python 3.5 installation:
Python 3.5.2 [MSC v.1900 64 bit (AMD64)] on win32
Notice the 64 bit part.
Otherwise, it gives the above error.
You are going to install tensorflow-1.0.1-cp35-cp35m-win_amd64.whl, therefore double check your correct version (mostly this is happening you have both Python 2.7 and 3.5).

when installing python, on the install window, check the box "Active path"(something like that), which builds up a path link. So you can run "pip3 install" at anywhere.

Typing the python command before that should do the trick. In my case (on Windows 8.1 with Python 3.6), I had to type 'py' instead of 'python' as follows:
py -m pip install --upgrade tensorflow
The answer depends on the system you're using.

The issue is your path in the cmd is not that of where your python scripts are placed. In this case you can either navigate to "AppData\Local\Programs\Python\Python36\Scripts" in your terminal and then run the command or you can simply put C:\Users\Your User Name\AppData\Local\Programs\Python\Python36\Scripts to Path variable.
Then re-launch your cmd and type "pip3 install tensorflow" and see the feel the happiness :)

I just experienced the same issue, most likely you downloaded a zipped version of python, then unzipped it, and added it to $PATH just like me, python can work but pip3 cannot, and python -m pip cannot either.
fix solution is to download a executable version of python, then follow common installation steps, pip3 is selected by default, then everything is OK now.