Randomly Split a Vector into Groups of Given Sizes

Randomly assigns the elements of a vector x into groups with predefined sizes given by groupSizes. The grouping is performed without replacement and each element is assigned to exactly one group.

Usage

randGroupSplit(x, groupSizes)

Arguments

x

a vector containing the elements to be split into groups.

groupSizes

an integer vector specifying the sizes of the groups. The sum of groupSizes must equal length(x). If the vector is named, the names are used as group names in the result.

Value

a list of vectors, where each element corresponds to one group. The length of the list equals length(groupSizes).

Details

This function is useful for random group assignments, for example in teaching settings, simulations, or experimental designs where groups of unequal sizes are required. It uses sample(), so results can be made reproducible with set.seed().

See also

Other combinatorics: combN(), combPairs(), combSet(), pairApply(), permn(), sampleX()

Examples

# Split letters into 3 groups of sizes 4, 3, and 5
set.seed(123)
randGroupSplit(LETTERS[1:12], groupSizes = c(4, 3, 5))
#> $`1`
#> [1] "A" "D" "H" "K"
#> 
#> $`2`
#> [1] "E" "G" "L"
#> 
#> $`3`
#> [1] "B" "C" "F" "I" "J"
#> 

# named groups
randGroupSplit(LETTERS[1:7], groupSizes = c(treat = 4, ctrl = 3))
#> $treat
#> [1] "A" "E" "F" "G"
#> 
#> $ctrl
#> [1] "B" "C" "D"
#>