When I run Python from the terminal and from Atom, different versions of python are called. As a consequence, there are packages that I can call without problems from the terminal but that I cannot call from Atom. Here are the details: 
When calling python from the terminal, I get version 3.7.1 
$ python
Python 3.7.1 | packaged by conda-forge | (default, Nov 13 2018, 09:50:42) 
[Clang 9.0.0 (clang-900.0.37)] :: Anaconda custom (64-bit) on darwin
(I get exactly the same if I type python3instead)
Now when looking at the python version from Atom i get version 3.6.5 with
>>> import sys
>>> print(sys.version
3.6.5 | packaged by conda-forge | (default, Apr  6 2018, 13:44:09) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)]
how come? how can I make Atom get the same version as the version the Terminal is getting?
Failed attempts
Looking at the PATH with the command import sys and then print(sys.path) here is what I get: 
From Atom:
['', '/anaconda3/lib/python36.zip', '/anaconda3/lib/python3.6', 
'/anaconda3/lib/python3.6/lib-dynload', '/anaconda3/lib/python3.6/site-packages',
'/anaconda3/lib/python3.6/site-packages/aeosa', '/anaconda3/lib/python3.6/site-packages/cycler-0.10.0-py3.6.egg', 
'/anaconda3/lib/python3.6/site-packages/IPython/extensions', '/Users/mymac/.ipython']
From the Terminal:
['', '/Users/mymac/anaconda3/lib/python37.zip', 
'/Users/mymac/anaconda3/lib/python3.7', 
'/Users/mymac/anaconda3/lib/python3.7/lib-dynload', 
'/Users/mymac/anaconda3/lib/python3.7/site-packages', 
'/Users/mymac/anaconda3/lib/python3.7/site-packages/aeosa']
It seems Atom is using the version of Python of pyenv given the following command and output: 
$ pyenv versions
* system (set by /Users/mymac/.pyenv/version)
  3.6.5
according to the github page of pyenv. I entered pyenv virtualenv 3.7.1. Then when entering $ pyenv versions at least the version 3.7.1 was in the list: 
* system (set by /Users/mymac/.pyenv/version)
  3.6.5
  3.7.1
But that didn't solve the problem with Atom
I then visited the conda page aboute managing environment and ran the following commands:
$ conda create --name myenv
It ran without problem, but the problem persists
I then tried to run more specifically $ conda create -n myenv python=3.7.1 but got: CondaValueError: prefix already exists: /Users/mymac/anaconda3/envs/myenv
As pointed by @jmh Then I tried: $ source activate 3.7.1 and got the following prompt: (3.7.1) user:~ user$
I could successfully choose the correct the correct virtualenv. But then upon opening Atom the problem persisted
 
     
    
