G. Grothendieck questions

G. Grothendieck answers

• 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
• How to return multiple columns from one function inside `mutate` and allow me to name the output columns?
• overwrite variable in parent function from inner function without making variable outside parent function
• How to use internal functions of a given package in my own functions
• How to replace numeric month with a month's full name
• Roll apply for partial time series in R
• How to Roxygenize a single R script file? [duplicate]
• dplyr equivalent to DF[DF==X] <- Y
• Separate a backreference from a number