How to downgrade python from 3 7 to 3 6

Question

I m trying to install tensorflow but it needs a Python 3 6 installation and I only have Python 3 7 installed  I tried to switch using brew and pyenv but it doesn t work    Does anyone know of a way to solve this problem

User · Answer

I would just recommend creating a new virtual environment and installing all the packages from the start as the wheels for some packages might have been installed for the previous version of the Python. I believe this is the safest way and you have two options.

Creating a new virtual environment with venv:

python3.6 -m venv -n new_env
source venv_env/bin/activate

Creating a conda environment:

conda create -n new_env python=3.6
conda activate new_env

The packages you install in an environment are built based on the Python version of the environment and if you do not carefully modify the existing environment, then, you can cause some incompatibilities between packages. That is why I would recommend a using a new environment built with Python 3.6.

User · Answer

Download and install Python 3 6 and then change the system path environment variable to that of python 3 6 and delete the python 3 7 path system environment variable  Restart pc for results

User · Answer

If you are working with Anaconda  then   conda install python 3 5 0   or maybe  conda install python 2 7 8   or whatever you want       might work

User · Answer

Download python 3 6 0 from https   www python org downloads release python-360   Install it as a normal package   Run cd  Library Frameworks Python framework Version  Run ls command and all installed Python versions will be visible here   Run sudo rm -rf 3 7  Check the version now by python3 -V and it will be 3 6 now

User · Answer

Create a python virtual environment using conda  and then install the tensorflow     conda create -n  environment-name  python 3 6   it may ask for installing python-3 6 if you don t have it already  Type  y  to proceed      activate  environment-name    pip install tensorflow   From now on  you can activate the environment whenever you want to use tensorflow   If you don t have the conda package manager  first download it from here  https   www anaconda com distribution

User · Answer

I was having trouble installing tensorflow with python 3 7 and followed these instructions to have a virtual environment setup with python3 6 and got it working  Download the Python3 6 tgz file from the official website  eg  Python-3 6 6 tgz  Unpack it with tar -xvzf Python-3 6 6 tgz cd Python-3 6 6 run   configure run make altinstall to install it  install vs altinstall explanation here    setting up python3 6 virtual environment for tensorflow  If you are using jupyter notebook or jupyter lab this can be helpful to choose the right virtual environment   python -m venv projectname source projectname bin activate pip install ipykernel ipython kernel install --user --name projectname   At this point  you can start jupyter  create a new notebook and select the kernel that lives inside your environment   virtual environment and jupyter notebooks  Hope this helps

User · Answer

A clean way without having to uninstall a previous version or reverting to additional software like Anaconda or docker  etc  is to download the Python 3 6 source code and install it as follows     mkdir  home  lt user gt  python3 6     configure --prefix  home  lt user gt  python3 6    make altinstall   To use it you either    add  home  lt user gt  python3 6 bin to your PATH  and lib to LD LIBRARY PATH  and be done with it   You may also need to add to your include path etc   depending on what you re trying to achieve exactly - but you get the idea  I hope    or  you create a virtual environment similar to this   home  lt user gt  python3 6 bin python3 6 -m venv env-python3 6    No sudo or root access required  No messing up your system

User · Answer

I just now downgraded my Python 3 9 to 3 6 because I wanted to use the librosa package but it does not support Python 3 9 still now  Steps -  Go to python official website Download the Python version which you want Install in your machine normally  Run python3 --version in the terminal and it will show this version of Python

User · Answer

brew unlink python   brew install --ignore-dependencies https   raw githubusercontent com Homebrew homebrew-core e128fa1bce3377de32cbf11bd8e46f7334dfd7a6 Formula python rb   brew switch python 3 6 5   pip install tensorflow

User · Answer

create a virtual environment  install then switch to python 3 6 5    conda create -n tensorflow python 3 7   conda activate tensorflow   conda install python 3 6 5   pip install tensorflow   activate the environment when you would want to use tensorflow

User · Answer

Here is a canonical summary which sums up different solutions for the variety of operating system Python runs on  What follows are possibilities for Microsoft Windows  Linux  macOS and Misc  As mentioned those are just possibilities - by no means do I claim to have a complete list whatsoever   Microsoft Windows Option 1 In general  it s suggested to use virtual environments  I highly suggest looking at the official Python documentation   With this approach  you easily can set up project-specific Python versions  as well as libraries   Easily manageable and the best part  There are lots of tutorials on the internet on how to approach this   Using VirtualEnv with multiple Python versions on windows https   www freecodecamp org news installing-multiple-python-versions-on-windows-using-virtualenv  etc   1   Open command prompt   quot cmd quot   and enter pip install virtualenv  2   Install your desired Python version via https   www python org downloads release  Remember  Do not add to PATH  3   Type into the command prompt  virtualenv  path to env -p  path to python install exe  whereas  path to env shall be the path where your virtual environment is going to be and  path to python install exe the one where your freshly  presumably  installed Python version resides  4   Done  You now have a virtual environment set up  Now  to activate the virtual environment execute the batch file which is located inside the  path to env Scripts activate bat   cf  this website or an official Python guide  Option 2 The basic option would be to uninstall the unwanted Python version and re-install the favored one from https   www python org downloads   To remove the  quot old quot  version go to Control Panel - gt   quot Uninstall a program quot  - gt  Search for  quot Python quot   - gt  Right-click on the Python name - gt  Uninstall  Bear in mind that Python usually has a PATH variable stored  hence you should remove it as well - Check the following links for this   https   support foundry com hc en-us articles 209642805-Q100127-How-to-delete-unset-environment-variables Remove unwanted path name from  path  variable via batch  Now double-check whether there are any remaining files where Python used to be stored  Usually  you can find all the Python files at either C  Program Files  x86  Pythonxx  C  Users username AppData Local Programs Pythonxx or C  Pythonxx or all of them  You might have installed it in another directory - check where it once was  Now after de-installing just re-install the wanted version by going to the download page and follow the usual installation process  I won t go into details on how to install Python   Lastly  you might check which version is currently installed by opening the command prompt and typing python -V  Option 3 This approach is pretty similar to the second one - you basically uninstall the old one and replace it by your favored version  The only thing that changes it the part regarding how to uninstall the unwanted Python distribution  Simply execute the Python3 installer you originally used to install Python  it s usually stored in your Python directory as mentioned above  for more assistance check out this   There you get an option to repair or uninstall  proceed by choosing uninstall  and follow the steps provided via the uninstaller  No matter how you uninstall Python  there are many resources on this topic  for example this Stack Overflow question or a problem thread a user by the name of Vincent Tang posted on the Stack Exchange site Super User  etc    just reinstall the wanted Python version by following the steps mentioned in Option 2  Option 4 Option 4 deals with Anaconda  Please refer to this site on how to install Anaconda on Windows  Step 9 is important as you don t want to install it as your default Python - you want to run multiple versions of Python   Choose whether to register Anaconda as your default Python  Unless you plan on installing and running multiple versions of Anaconda or multiple versions of Python  accept the default and leave this box checked   Follow the official tutorial I linked above  Once done you can create the following commands individually in the anaconda prompt  To overwrite the default python version system-wise use conda install python 3 6 or to create a virtual environment go ahead and use conda create -n  PYTHON36 ENV NAME python 3 6 anaconda whereas  PYTHON36 ENV NAME is the custom name you can set  Credit where credit is due - the user  CermakM from this thread strongly influenced this snippet  In my research I encountered a bunch of useful Stack Overflow threads - you might check them out if you go the tough road with Anaconda   How to downgrade the Python Version from 3 8 to 3 7 on windows  downgrade python version from 3 8 to lower one in a given conda environment  Option 5 What follows isn t a downgrade in the classical sense - though for the sake of completeness I decided to mention this approach as well  On Windows you re also able to run multiple Python versions - an infamous thread on StackOverflow deals with this question  thus I politely refer you to there for further reading purposes   Linux Option 1 Pretty analog to the third option for Windows I highly suggest you use a virtual environment such as Anaconda  Anaconda - or short conda - is also available on Linux  Check the official installation documentation here  Once again this thread is highly suggested on how to overwrite a Python version  respectively how to specifically create an environment with your wanted Python version  Option 2 Another highly suggested virtual environment is Pyenv  The user  Sawan Vaidya described in this Stack Overflow question on how to up-or downgrade a Python version with the help of Pyenv  You can either set a Python version globally or create a local environment - both explained in the mentioned thread  Option 3 Another user  namely  Jeereddy  has suggested to use the software package management system Homebrew  He explained this option thoroughly in this current question    brew unlink python   brew install --ignore-dependencies https   raw githubusercontent com Homebrew homebrew-core e128fa1bce3377de32cbf11bd8e46f7334dfd7a6 Formula python rb   brew switch python 3 6 5  Option 5 No need to reinvent the wheel - this thread is filled with lots of beautiful running approaches such as the one by  Sidharth Taneja   Download your wanted Python version from https   www python org downloads release and install it as a normal package  Run cd  Library Frameworks Python framework Version Execute ls to list all installed Python versions Run sudo rm -rf 3 7  removing Python version 3 7 - can be repeated for whatever version s  you want to delete Check python3 -v  it should display the version you originally wanted to have installed  Option 6 What a goldmine this thread is  As  nondetermistic has described in-depth  direct link to his post   Install Python source code as it is like this   Taken Python 3 6 as an example   mkdir  home  lt user gt  python3 6     configure --prefix  home  lt user gt  python3 6    make altinstall  You re now able to either add the downloaded version   home  lt user gt  python3 6 bin  to PATH as well as lib to LD LIBRARY PATH or just create a virtual environment by   home  lt user gt  python3 6 bin python3 6 -m venv env-python3 6  A very aesthetic and simple solution to run multiple Python versions on your system   macOS Option 1 Using pyenv with Homebrew - credit to  Shayan with his reply here  1   Installing pyenv with Homebrew  brew update brew install pyenv  2   Cloning the GitHub repository to get latest pyenv version   git clone https   github com pyenv pyenv git    pyenv  3   Defining the environment variables as follows echo  export PYENV ROOT  quot  HOME  pyenv quot    gt  gt     bash profile echo  export PATH  quot  PYENV ROOT bin  PATH quot    gt  gt     bash profile  4   Restarting shell so PATH change works exec  quot  SHELL quot   5   Checking the available Python versions pyenv install --list  6   Installing the wanted Python version  e g  3 6 pyenv install 3 6  7   Setting it globally  you can also go ahead and only use it in a certain environment  pyenv global 3 6  8   Check the Python version the system is using - your wanted   downgraded version should be displayed here  python3 --version  Option 2 Similar to previous approaches you can download Anaconda on macOS as well  For an installation guide click here  The usage is pretty much the same as I ve already described in Option 4 of the Windows guide  Please check out above  Other options In this case it s getting pretty repetitive  I kindly suggest you to check the following resources for further reading   https   prodevsblog com questions 125949 macos-how-to-downgrade-homebrew-python  https   www xspdf com resolution 51291818 html How to downgrade python version from 3 8 to 3 7  mac  https   weknowinc com blog running-multiple-python-versions-mac-osx   Misc When writing this post I had the problem of not knowing where to draw the line  When looking up the operating systems Python currently supports you get a huge list  including the ones I mentioned  i e  Linux  Microsoft Windows and macOS  though obviously different Linux distributions are single-handedly treated  e g  CentOS  Arch Linux or Fedora should deserve a spot as well - or shall I make separate options for Windows 10  7  etc   Due to the high degree of repetitiveness as far as modules like Homebrew  Conda or alike are concerned I decided to limit my list to the  quot main three quot  operating systems - distributions like Ubuntu  How do I downgrade my version of python from 3 7 5 to 3 6 5 on ubuntu   CentOS  How to downgrade python version on CentOS   can be easily researched on Stack Overflow  Most often than not you can apply solutions from the Linux tab for said distributions  The same goes with Windows and macOS  versions

User · Answer

For those who want to add multiple Python version in their system  I easily add multiple interpreters by running the following commands   sudo apt update sudo apt install software-properties-common sudo add-apt-repository ppa deadsnakes ppa sudo apt install python 3 x x then while making your virtual environment choose the interpreter of your choice

User · Answer

pyenv can be used in Linux MacOS for python version management  pyenv-win is the fork of pyenv which can be used on Windows  Installation MacOS Tested on Mac Catalina  Install pyenv  brew install pyenv   Add following to your shell config file    bashrc  bash profile - For Bash  zshrc - For Zsh  export PYENV ROOT  quot  HOME  pyenv quot  export PATH  quot  PYENV ROOT bin  PATH quot  eval  quot   pyenv init -  quot    Restart your shell  Start a new shell or run exec  quot  SHELL quot  in your current shell    Linux   Windows on Linux Subsystem Tested on Arch Linux  Install pyenv on your system  curl https   pyenv run   bash   Follow same steps as in Step 2 and 3 of MacOS installation    Windows  Install pyenv-win on Windows  In Powershell pip install pyenv-win --target  quot  HOME  pyenv quot   In cmd exe pip install pyenv-win --target  quot  USERPROFILE   pyenv quot    Setup the environment variables using Powershell Terminal   System Environment   SetEnvironmentVariable  PYENV   env USERPROFILE    quot   pyenv pyenv-win  quot   quot User quot    System Environment   SetEnvironmentVariable  PYENV HOME   env USERPROFILE    quot   pyenv pyenv-win  quot   quot User quot    System Environment   SetEnvironmentVariable  path    HOME    quot   pyenv pyenv-win bin  quot     HOME    quot   pyenv pyenv-win shims  quot     env Path  quot User quot     Close and re-open your terminal  Run pyenv --version on the terminal  a  If the return value is the installed version of pyenv  then continue below  b  If you receive a command not found error  ensure the environment variables are properly set via the GUI  This PC   Properties   Advanced system settings   Advanced   Environment Variables      PATH c  If you receive a command not found error and you are using Visual Studio Code or another IDE with a built in terminal  restart it and try again   Run pyenv rehash from the home directory    Usage Check installed python versions pyenv versions  Example   pyenv versions   system  set by  home souser  pyenv version    3 6 9  Installed a specific python version pyenv install  lt version-number gt   Uninstall an installed python version pyenv uninstall  lt version-number gt   Set a python version as system-wide python version pyenv global  lt version-number gt     lt version-number gt  is the name assigned to your python in output of  pyenv versions   Example   python --version Python 3 9 1   pyenv global 3 6 9   python --version Python 3 6 9  Set a python version for a directory and all it s sub-directories pyenv local  lt version-number gt     lt version-number gt  is the name assigned to your python in output of  pyenv versions   Example   tmp temp  python --version Python 3 9 1   tmp temp  pyenv local 3 6 9   tmp temp  python --version Python 3 6 9  For more details  you can check the Github repos   pyenv and pyenv-win

User · Answer

If you use anaconda  you can just create a new environment with the specified version  In case you don t want to keep the existing version 3 7  you can just uninstall it and install it from here

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