Frank

Frank has asked 19 questions and find answers to 477 problems.

Stats

About

Here's an R tutorial.

"I mean, a horse is a horse of course, but who rides is important."

Frank questions

fill rows downward for a column with NAs (with R base or data.table)
splitting (1:n)[boolean] into contiguous sequences
accessing Y columns with duplicated names in j of X[Y, j] merges
print the data.table package's .onAttach messages with knitr
Clean, simple function factories in R
Using data.table's .() shortcut in quoted expressions
lapply-ing with the "$" function
Efficiently computing a linear combination of data.table columns
data.table `:=` assignment expressions with dynamic inputs (existing columns) and outputs (new column names)
Saving plots in a data.table list column

Frank answers

Group by ID, each element of the new table is a vector
Reshaping data using tidyr
aggregate data.table to rows of intervals of original values
Divide Groups by # of samples in each group in R
Transform multiple columns with a function that uses different arguments per column
Extract rows with duplicate values in two or more fields but different values in another field
How to select all columns plus an additional expression
Matching column in dataframe by nearest values in column of other dataframe
keep specific duplicate based on lookup table in R
How to do row wise operations on .SD columns in data.table