Frank

Frank has asked 19 questions and find answers to 446 problems.

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"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

Subset a dataframe with 3 threshold conditions of corresponding ID names
data.table := assigning and grouping
Update column of dataframe1 based on column of dataframe2 + create new row if column1 is not empty
Rename by list() variable name rather than index in R
How to sort odd and even numbers of an array in a specific format
R-Loop through data frame and count values greater than a value and removing rows
R generating new data.table slowdown
R data.table ordered column lookup
Get names of column with max value for each row
Common elements of vectors with multiple elements