ffbase: bySum – R documentation

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bySum

Fast conditional sum

bySum works like a very fast version of tapply with (weighted) FUN=sum.

bySum(x, by, na.rm = FALSE, weight = NULL, ...)

`x`	`numeric` vector to be summed
`by`	(list of) `factor(s)` for which the sum will be calculated
`na.rm`	`logical` If `TRUE` `NA` values will be removed
`weight`	`numeric` with of same length as `x`
`...`	not used

array with dimensions of by

bySum(warpbreaks$breaks, warpbreaks$wool)
bySum(warpbreaks$breaks, warpbreaks[,-1])

Basic Statistical Functions for Package 'ff'

v0.13.3

GPL-3

Authors

Edwin de Jonge, Jan Wijffels, Jan van der Laan

Initial release