pyenv local - can't set a Python version by its number despite the fact that it's installed

Question

Any suggestions on how you set the version of Python for pyenv?

E.g.

$ python3
Python 3.6.0 (v3.6.0:41df79263a11, Dec 22 2016, 17:23:13) 
$ pyenv local
pyenv: no local version configured for this directory
$ pyenv local 3.6.0
pyenv: version `3.6.0' not installed
$ pyenv local v3.6.0:41df79263a11
pyenv: version `v3.6.0' not installed

Answer 1

You need to set up an virtual env first. For example, you can create a env called pyenv360 by

$ pyenv virtualenv 3.6.0 pyenv360

And set it as your default python for your folder my-folder by

$ cd my-folder
$ pyenv local pyenv360

By doing this, whenever you enter this folder, it'll start using pyenv360 which references python 3.6.0 in this case.

You can check if it's working by:

$ pyenv local

which should show pyenv360.

Answer 2

_{(Assuming you installed pyenv according to the official instructions.)}

pyenv recognizes two kinds of Python installations:

• system -- Python executables from PATH, regardless of their versions
• numbered versions -- installed with pyenv install under $PYENV_ROOT/versions

pyenv considers the former installations outside its control, so its commands don't take their versions into account when looking for a specific version.

---

To find out which installation, from pyenv's POV, your python3 refers to, check

• pyenv versions
  • whether the selected Python 3 version is "system"; or
• which python3 (and pyenv which python3 if the former points into <pyenv root>/shims/)
  • whether the result points to outside $PYENV_ROOT

If your 3.6.0 installation is indeed outside of pyenv's control, you need to select it with pyenv local system and make sure on your own that your PATH is arranged to point to it.

• More specifically, that your PATH first points to <pyenv_root>/shims and then to the correct python3
  • You can use which -a python3 to quickly check that