subsetDT: Subset a 'data.table' with random subsampling within 'by'...
In PredictiveEcology/LandR: Landscape Ecosystem Modelling in R

Subset a data.table with random subsampling within by groups

1	subsetDT(DT, by, doSubset = TRUE, indices = FALSE)

`DT`	A `data.table`
`by`	Character vector of column names to use for groups
`doSubset`	Logical or numeric indicating the number of subsamples to use
`indices`	Logical. If `TRUE`, this will return vector of row indices only. Defaults to `FALSE`, i.e., return the subsampled `data.table`

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library(data.table)
dt <- data.table(Lett = sample(LETTERS, replace = TRUE, size = 1000), Nums = 1:100)
dt1 <- subsetDT(dt, by = "Lett", doSubset = 3)