How to implement coalesce efficiently in R

Question

Background

Several SQL languages (I mostly use postgreSQL) have a function called coalesce which returns the first non null column element for each row. This can b

Answer 1

From data.table >= 1.12.3 you can use fcoalesce.

library(data.table)
fcoalesce(a, b, c)
# [1]  1  2 NA  4  6

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For more info, including a benchmark, see NEWS item #18 for development version 1.12.3.