November 2019 Updates

New Introduction To rasterio page.

Added information on masked arrays to the Numpy page.
Added Euler Angle support (e.g. RPY) to the 3D rotations calculator.
New introduction to different map projections.
Added a new React page.

October 2019 Updates

Updated the mv (move) page with information on using extended bash glob extensions to provide exclusion patterns.

$ mkdir new_sub_dir # Create a new sub-directory to move all files/directories in PWD into
$ mv !(new_sub_dir) new_sub_dir # Move all files/directories in PWD into new_sub_dir, excluding new_sub_dir itself (avoiding the obvious recursion problem)

The Introduction To Rotation Matrices page has been updated with tutorials/example on how to combine rotation matrices and how to calculate the rotation matrix to describe the rotation between two reference frames, as well as a section on how to convert RPY (roll-pitch-yaw, or Euler angles) to rotation matrices.
$$ \mathbf{R} = \begin{bmatrix} \hat{u_x} & \hat{v_x} & \hat{w_x} \\ \hat{u_y} & \hat{v_y} & \hat{w_y} \\ \hat{u_z} & \hat{v_z} & \hat{w_z} \end{bmatrix} $$
Added an interactive 3D rotation visualizer to the Quaternion page, which shows you how a right-hand coordinate system XYZ is rotated in 3D space by either a rotation matrix, quaternion, or angle-axis rotation. This tool is also very useful to convert between the three ways of describing a rotation (when you enter a rotation in one notation, the other two get updated automatically).

A screenshot of the 3D rotation visualizer and converter.

September 2019 Updates

The du (disk usage) page now has information on the -x flag which is used count the space used on one filesystem only.
New Introduction To Asynchronous Programming In Python with information on asynchronous programming in Python, including the keywords async/await, event loops, futures, coroutines and more.