Sample a vector by a group

Return a sample from a vector within a grouping variable.

sample_bygroup(x, group, size = NULL, replace = FALSE)

Arguments

x	any vector
group	a grouping vector equal in length to length(x)
size	the number of items to sample within each group, as a positive number or a vector of numbers equal in length to the number of groups. If NULL, the sampling is stratified by group in the original group sizes.
replace	logical; should sampling be with replacement?

Value

x resampled within groups

Examples

set.seed(100)
grvec <- c(rep("a", 3), rep("b", 4), rep("c", 3))
quanteda:::sample_bygroup(1:10, group = grvec, replace = FALSE)
#>  [1]  2  1  3  7  6  4  5  9 10  8
quanteda:::sample_bygroup(1:10, group = grvec, replace = TRUE)
#>  [1]  2  2  3  5  5  6  6 10 10  9
quanteda:::sample_bygroup(1:10, group = grvec, size = 2, replace = TRUE)
#> [1] 1 3 6 7 9 8
quanteda:::sample_bygroup(1:10, group = grvec, size = c(1, 1, 3), replace = TRUE)
#> [1]  2  6  9  8 10