R and RStudio

R
A freely available language and environment for statistical computing and graphics.
RStudio Desktop
RStudio Desktop (Free) is an integrated development environment (IDE) for R. It includes a console, syntax-highlighting editor that supports direct code execution, as well as tools for plotting, history, debugging and workspace management.

Markdown

&what;
A quick, interactive reference of 14,500 HTML character entities and common Unicode characters, 8859-1 characters, quotation marks, punctuation marks, accented characters, symbols, mathematical symbols, and Greek letters, icons, and markup-significant & internationalization characters.
Basic Syntax
The Markdown elements outlined in John Gruber’s design document.
Colab Markdown Guide
Colab has two types of cells: text and code. Text cells are formatted using a simple markup language called Markdown. This notebook walks you through the basic syntax and how it appears once rendered.
Linking Images to Markdown Files
In order for images to appear on your web page that is rendered from markdown, you need a publicly accessible URL for the image. This guide shows you have to access these links from images stored in Dropbox, Drive, and Wikimedia.
Markdown Cheatsheet
Adam Pritchard’s quick reference and showcase of Markdown on GitHub.
R Markdown Cheatsheet
(PDF) Condensed info on formatting with markdown in R.
Stackedit.io
An in-browser markdown editor and processor. Note that there are likely minor variations and discrepancies between Markdown processors.
Thesaurus of Mathematical Languages
A quick reference of mathematical computation environments for computer algebra, numeric processing, and data visualization including synonymous commands in MATLAB, Python, R, and others.1

  1. Copyright ©2006,2008 Vidar Bronken Gundersen, http://mathesaurus.sf.net/.↩︎