Running Anaconda Python within emacs on Windows

Question

I have a Windows 10 machine, with the official GNU emacs Windows build, and Anaconda Python 3.7.3. I can't get Python to properly run within emacs. Whenever I start Python, I get the message:

Python 3.7.3 (default, Mar 27 2019, 17:13:21) [MSC v.1915 64 bit (AMD64)] :: Anaconda, Inc. on win32

Warning:
This Python interpreter is in a conda environment, but the environment has not been activated.  Libraries may fail to load.  To activate this environment please see https://conda.io/activation

Type "help", "copyright", "credits" or "license" for more information.

And numpy, scipy, etc won't load. I have tried several things with the pyvenv and elpy packages, all to no avail. From a DOS prompt, I type 'activate' to activate the conda env. I haven't setup any venv's of my own.

Answer 1

Provided that you added the folders paths of your conda install in Windows' %PATH% variable[*], the following should work :

1. M-x shell

2. In the shell, run conda activate base. This will load the environment and allow you to use the libraries (like numpy).

3. In the same shell, run python -i (or ipython -i). The -i forces a prompt. Without it, the shell hangs in Emacs, I don't know why (it doesn't in cmd).

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I personally automated this process by creating a batch file called my-python.bat. I placed it in a folder named my-batch-files which I have referenced in %PATH% [*]. Here's the bat file :

@echo off
conda activate base && python -i

That way you can call directly my-python from the shell — whether it be on Emacs or on cmd — and have a working ipython shell, with all DLLs loaded.

Plus, if you change python-shell-interpreter to my-python, you get the default functions from python-mode run-python (C-c C-p) and python-shell-send-buffer (C-c C-c) working.

Caveat : At this time, images' display (with matplotlib.pyplot) still does not work properly. I'm working on it. If someone has ideas...

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_{[*] Windows -> Environment variables -> System Variables -> Path -> Edit. The paths should look like this (check them beforehand !) : C:\Users\YOUR_USER_NAME\AppData\Local\Continuum\anaconda3\Scripts and C:\Users\YOUR_USER_NAME\AppData\Local\Continuum\anaconda3.}

_{You'll have to relaunch the shell (and Emacs !) for the environment variables to be taken into account. You can check the variable value by typing echo %PATH% in your shell.}

Answer 2

This solved my issue of numpy failing to load on import when using Anaconda3/python on Windows 10 from my Emacs session:

https://github.com/ContinuumIO/anaconda-issues/issues/10884#issuecomment-499805821