Submitted by: Arun ; Assigned to: Nobody; R-Forge link

For GForce

• gsum, gmean
• .N
• gmin, max
• median
• head(.SD, 1), tail(.SD, 1), last(x)
• [ for length-1 subsets
• gvar
• gsd
• gprod
• .SD[which.min()], .SD[which.max()]
• guniqueN
• gpaste??
• quantile
• covariance
• correlation
• kurtosis
• skewness

When GForce is upgraded to work with :=:

• cumulative functions
• rolling / window functions

Utility function

• lead, lag

It should return a list. That is,

x <- 1:5
lag(x, 1:2)
# [[1]]
# [1] NA  1  2  3  4
# 
# [[2]]
# [1] NA NA  1  2  3