See the original description in base::asplit.
asplit(x, MARGIN)# get function from namespace instead of possibly getting
# implementation shipped with recent R versions:
bp_asplit = getFromNamespace("asplit", "backports")
x = matrix(1:6, 2, 3)
bp_asplit(x, 1)
#> [[1]]
#> [1] 1 3 5
#>
#> [[2]]
#> [1] 2 4 6
#>