Why doesn't a new Conda environment come with packages like numpy?

Question

I am going through the painful process of learning how to manage packages/ different (virtual) environments in Python/Anaconda. I was told that Anaconda is basically a python installation with all the packages I need (e.g. numpy, scipy, sci-kit learn etc).

However, when I create a new environment, none of these packages is readily available. I cannot import them when using PyCharm with the newly created environment. When I check the Pycharm project interpreter, or the anaconda navigator environments tab, It seems that indeed none of these packages are installed in my new environments. Why is this? It doesn't make sense to me to provide all these packages, but then not make them ready for use when creating new environments. Do I have to install all these packages manually in new env's or am I missing something?

Kindest regards, and thanks in advance.

Answer 1

The reason the default python environment doesn't come with numpy is because maybe you don't want numpy in the environment. Imagine writing an API (or general software package) where your users may or may not have access to numpy. You might want to run tests to make sure your software fails gracefully or has a pure python fallback if numpy is not installed on your user's machine. Conda environments provide this (insanely useful) benefit. Of course, the package in question doesn't have to be numpy. There are some more esoteric packages where this type of testing is useful.

Furthermore, you can create a conda environment with numpy pre-installed, or any other package you want pre-installed (just add them to the end of the conda create command):

conda create --name my-env-name numpy

Answer 2

Anaconda comes with available packages such as numpy, scipy, and sci-kit learn, but if you want to use them within your environment, you must:

1) Create the environment:

conda create --name new_env 

2) Activate the environment:

source activate new_env 

3) Install the desired package using conda install

conda install numpy

If you'd like to create a new environment that includes installations of all available Anaconda packages, see create anaconda python environment with all packages. You can include anaconda in the list of packages to install in the environment, which is a 'meta-package' meaning 'all the packages that come with the Anaconda installation'.