G. Grothendieck questions

G. Grothendieck answers

• Common operations between multiple S3 methods
• Finding `n1` TRUEs wrapped in between two `n2` FALSEs, the whole thing wrapped in between `n3` TRUEs, etc
• R: How to take the min and max or other functions of every n rows
• Create a confusion matrix from a dataframe
• making a triangular (or generally a square) matrix symmetirc
• How do I make a function in R to check for data errors?
• How does an environment remember that it exists?
• Lagged Regression
• Determining Which Points on the Perimeter of a Circle Fall Between Two Other Points That Are on Its Radius
• Adding new column with diff() function when there is one less row in R