sample_rows: Title
In m-dz/mdmisc:

Description Usage Arguments Value Examples

Title

1	sample_rows(dt, pct = NULL, vol = NULL, grouping = NULL, sort = FALSE)

`dt`	`data.table` to sample from
`pct`	Percentage of data sampled
`grouping`	Grouping (a `character vector`)
`sort`	c('no', 'id', 'gr')

data.table with sampled data

set.seed(2016)
size <- 10
dt <- data.table(
  id = 1:size, A = sample(letters[1:3], size, replace = TRUE), B = 'N',
  C = sample(1:100, size, replace = TRUE) + sample(30:70, size, replace = TRUE))
set.seed(2016)
sample_rows(dt, 0.5, grouping = 'A')
sample_rows(dt, 0.5, grouping = 'A', sort = TRUE)
sample_rows(dt, 0.5, grouping = c('A','B'), sort = TRUE)