Install ROOT with specific python version on docker container

[Wile_E_Coyote]

Python: No module named 'root'

You MUST use EXACTLY the same Python version (and the same compiler) that your ROOT binaries were built for (otherwise, expect mysterious crashes anywhere, anytime): root-config --python-version # C/C++ calling python ; root-config --python2-version # python 2 calling C/C++ ; root-config --python3-version # python 3 calling C/C++ ; BTW. Remember to “source /the/location/of/ROOT/bin/thisroot.sh” to add your ROOT executables and libraries to your environment (when ROOT is not installed in some “…