Conda Basics

Overview

In the previous lesson we showed you a cloud-based environment for our work during the hackweek. What happens after the event when you want to go home and work with all the libraries we showed you? You will likely also want to have a functioning version of Python on your local laptop if that is not already in place. So this lesson takes you through our recommended procedure for doing that. We suggest you get this set up in advance so that we can help you troubleshoot when you arrive.

Python Software

Python software is distributed as a series of libraries that are called within your code to perform certain tasks. There are many different collections, or distributions of Python software. Generally you install a specific distribution of Python and then add additional libraries as you need them. There are also several different versions of Python. The two main versions right now are 2.7 and 3.7, although Python 2.7 will not be supported past 2020. Some libraries only work with specific versions of Python.

So even though Python is one of the most adaptable, easy-to-use software systems, you can see there are still complexities to work out and potential challenges when delivering content to a large group. Therefore we have a number of different ways that we are trying to simplify this process to maximize your learning during the hackweek.

We also provide instructions for using Anaconda, which is our recommended Python distribution, for installing and working with Python on your local computer. We can assist in setting up "conda" environments that will simplify the gathering of Python libraries and version specific to the tutorial you are working on.

What is Conda?

Conda is an open source package and environment management system for any programming languages, but very popular among python community, for installing multiple versions of software packages, their dependencies and switching easily between them. It works on Linux, OS X and Windows.

Installing Miniconda

Windows

Click here to download the proper installer for your Windows platform (64 bits). We recommend to download the Python 3 version of Miniconda. You can still create Python 2 environments using the Python 3 version of Miniconda.

When installing, you will be asked if you wish to make the Anaconda Python your default Python for Windows. If you do not have any other installation that is a good option. If you want to keep multiple versions of python on your machine (e.g. ESRI-supplied python, or 64 bit versions of Anaconda), then don't select the option to modify your path or modify your windows registry settings.

Linux and OSX

You may follow manual steps from here similar to the instructions on Windows (see above). Alternatively, you can execute these commands on a terminal shell (in this case, the bash shell):

# For MacOSX
url=https://repo.continuum.io/miniconda/Miniconda3-latest-MacOSX-x86_64.sh
# For Linux
url=https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
wget $url -O miniconda.sh
bash miniconda.sh -b -p $HOME/miniconda
export PATH="$HOME/miniconda/bin:$PATH"
conda update conda --yes

Installing Anaconda (Optional)

NOTE: If you don't have time or disk space for the entire distribution do not install Anaconda. Install only Miniconda, a bootstrap version of Anaconda, which contains only Python, essential packages, and conda. We will provide an environment file to install all the packages necessary for the hackweek.

Anaconda is a data science platform that comes with a lot of packages. At its core, Anaconda uses the conda package management system.

The list of packages included can be found here

To install Anaconda, please click on the link below for your operating system, and follow the instructions on the site.
Once Anaconda installation step is finished run python in the command line to test if Anaconda is installed correctly. Note: For windows, please use the Anaconda prompt as the command line. It should be installed with your installation of Anaconda If Anaconda is installed correctly, you should have this prompt, which emphasizes Anaconda:

$ python
Python 3.7.3|Anaconda custom (x86_64)| (default, Mar 27 2019, 22:11:17)
...

Installing Python

We will be using Python 3.6 or 3.7 during the week (either will work). Since Anaconda (on Linux) expects you to work in the "bash" shell, if this is not already your default shell, you need to set it to be so (use the "chsh -s /bin/bash" command to change your default shell to bash) or just run an instance of bash from the command line before issuing "Conda" commands (/bin/bash or where it is located on your system).

If you are already familiar with Python 2.7, you can take a look at the syntax differences here, but the main point to remember is to put the print statements in parentheses:

print('Hello World!')

$ conda create -n py37 python=3.7

To use Python 3.7:

$ conda activate py37

To check if you have the correct version:

$ python --version