[SOLVED] Python/Tkinter : ModuleNotFoundError: No module named '_tkinter'

Issue

This is my first post StackOverflow, I will try to make it as correct and complete as possible if you have any tips to improve my post I will gladly accept it.

I'm having trouble running code written in Python that uses Tkinter.

I will try to describe in detail my actions to facilitate the identification of the error.

I started a course at Coursera on DSP (Digital Signal Processing) where it is suggested to install a tool written in python (and a little bit of C). I'm using Arch Linux.

link on Github: sms-tools repo

Using pyenv/virtualenv/virtualenvwrapper I created an environment with Python 3.7.5, as recommended in the "How to use" section of the repository.

I installed the required libraries in my environment by pip:

%pip install ipython numpy matplotlib scipy cython

I compiled some C functions in the "/sms-tools/software/models/utilFunctions_C"

directory with the following command:

%python compileModule.py build_ext --inplace

Finally, I run the models GUI in the directory "/sms-tools/software/models_interface"

%python models_GUI.py

and I get the following message:

Traceback (most recent call last):
  File "models_GUI.py", line 6, in <module>
    from Tkinter import *   ## notice capitalized T in Tkinter 
ModuleNotFoundError: No module named 'Tkinter'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "models_GUI.py", line 9, in <module>
    from tkinter import *   ## notice lowercase 't' in tkinter here
  File "~/.pyenv/versions/3.7.5/lib/python3.7/tkinter/__init__.py", line 36, in <module>
    import _tkinter # If this fails your Python may not be configured for Tk
ModuleNotFoundError: No module named '_tkinter'

I will now describe some of my attempts to solve the problem:

Looking at Tkinter section in Python Wiki I tried installing Tcl and Tk.

%sudo pacman -S tk

but it was already installed. after that I tried installing with pip:

%pip install tk

and

%pip install tkinter

and the error remains the same.

I also tried to create a symlink with this code: %ln -s /usr/lib/python3.8/lib-dynload/_tkinter.cpython-38-x86_64-linux-gnu.so _tkinter.cpython-38-x86_64-linux-gnu.so

the symlink was created in the following folders:

~/.ve/Coursera_DSP/lib/python3.7/lib-dynload

and

.pyenv/versions/3.7.5/lib/python3.7/lib-dynload

But I still get the same error.

I appreciate it if anyone has any suggestions and I apologize for the language errors since English is not my mother tongue.

After an incessant search on the internet, I believe the problem is related to pyenv and TCL/TK. I don't understand much about the subject but I suspect that in the creation of the environment by virtualenv python has lost the connection with TCL/TK. Does that make any sense?

Solution

Here is step by step guide to make IDLE and tkinter work. Working for me on macOS Catalina. Should be easily adapted to Linux environment:

1. install tcl-tk with Homebrew. In shell run brew install tcl-tk
2. in shell run echo 'export PATH="/usr/local/opt/tcl-tk/bin:$PATH"' >> ~/.zshrc
3. reload shell by quitting Terminal app or run source ~/.zshrc
4. after reloaded check that tck-tk is in $PATH. Run echo $PATH | grep --color=auto tcl-tk. As the result you should see your $PATH contents with tcl-tk highlighted
5. now we run three commands from Homebrew's output from step #1
   1. in shell run export LDFLAGS="-L/usr/local/opt/tcl-tk/lib"
   2. in shell run export CPPFLAGS="-I/usr/local/opt/tcl-tk/include"
   3. in shell run export PKG_CONFIG_PATH="/usr/local/opt/tcl-tk/lib/pkgconfig"
6. if you have your Python version already installed with pyenv then uninstall it with pyenv uninstall <your python version>. E.g. pyenv uninstall 3.8.2
7. set environment variable that will be used by python-build. In shell run PYTHON_CONFIGURE_OPTS="--with-tcltk-includes='-I/usr/local/opt/tcl-tk/include' --with-tcltk-libs='-L/usr/local/opt/tcl-tk/lib -ltcl8.6 -ltk8.6'" Note: in future use tck-tk version that actually installed with Homebrew. At the moment of posting 8.6 was the actual
8. finally install Python with pyenv with pyenv install <version>. E.g. pyenv install 3.8.2

Test

1. in shell run pyenv global <verion that you've just installed>
2. now check IDLE. In shell run idle. You should see IDLE window without any warnings and "text printed in red".

3. now check tkinter. In shell run python -m tkinter -c "tkinter._test()". You should see test window like on the image:

That's it!

My environment:

check this is something went wrong executing steps above:

1. macOS Catalina
2. zsh (included in macOS Catalina) = "shell" above
3. Homebrew (installed with instructions from Homebrew official website)
4. pyenv (installed with Homebrew and PATH updated according to pyenv official readme from GitHub)
5. Python 3.8.x - 3.9.x (installed with pyenv install <version> command)

Answered By - nickolay