Which Python version is installed in another conda env

Question

How can I find out which Python version is installed in a conda environment where I know the name, but do not want to activate that environment?

Background: I have chosen the lazy way to get python3.6 on my Ubuntu 14.04 machine and installed conda. But I would like to add certain directories to my PYTHONPATH depending on whether the environment has python2.x or python3.x and I plan to do this by wrapping conda's activate like so:

PYMAJOR=$(a_miracle_occurs $CONDAENV)
BASHRC=$(cat <<EOF
source ~/.bashrc
source activate $CONDAENV
export PATH=...
export PYTHONPATH=".../modules$PYMAJOR"
"
EOF
)
bash --rcfile <(echo "${BASHRC}")

I have no compatibility issues with subversions of python and I do not want to setup.py develop the modules in the PYTHONPATH-to-be because there are still too many changes, also on structural level.

Remark: I am aware of conda list -n ENVNAME but this would involve parsing human readable output and I would feel better off to have something retrieving the info in machine readable form.

Answer 1

Here is a one-liner that will print the environments and the associated python versions:

conda env list | grep -v "^$\|#" |awk '{print $1;}'|xargs -I{} -d "\n" sh -c 'printf "Env: {}\t"; conda list -n {} |grep "^python\s";'

Here is a sample output:

Env: base   python                    2.7.14              h1571d57_29  
Env: python37   python                    3.7.0                hc3d631a_0  

Rationale: Get the list of environments with conda env list, exclude empty lines and #, parse, print the environment packages with conda list -n <env> and grep for python.

You are welcome to adapt the formatting to your liking.

Answer 2

I am not at all familiar with anaconda and everything that follows is a wild guess. If anaconda uses virtualenv internally, the virtualenv should be installed into some directory (maybe something like $ANACONDA_HOME/envs/$CONDAENV?).

If that's the case, then the Python version should be retrievable by simply running $ANACONDA_HOME/envs/$CONDAENV/bin/python --version.

EDIT to address OPs comment:

To only return the version string try:

$ANACONDA_HOME/envs/$CONDAENV/bin/python -c 'import platform; print(platform.python_version())'
>>> 3.6.0