Filtering faces (keep, remove, convert, ignore)

At the table

Rules often treat faces differently: “only 5s and 6s can appear,” or “1–4 don’t count toward the total.” Those are face filters on each die—not the same as “total ≥ 15” from lesson 4.

Try it

Copy the script into the playground editor and click Run.

The script

↗output("high_die", d(6).keep(5..))
output("conditional_pool_sum", dice_pool(3, 6).keep(5..).sum())
output("ignored_pool_sum", dice_pool(3, 6).ignore(1..4).sum())

• keep(5..) drops non-matching faces (here 1–4), then renormalizes so only 5 and 6 remain.
• ignore(1..4) is shorthand for convert(1..4, 0): low faces still roll, but count as 0 when you sum.
• Face specs use the same shapes as in API conventions: a single face, [1, 2], ranges like 5.., or at_least(5).
• remove(1..4) on a d6 is the same die as keep(5..).

keep vs ignore vs p_ge

Try this

• Compare means of d(6).keep(5..) (5.5) and dice_pool(3, 6).ignore(1..4).sum() (5.5)—same mean, different distributions.
• Try keep(..2) for “only 1 or 2 can appear.”

high_die · DieRoll · mean 5.500

conditional_pool_sum · DieRoll · mean 16.500

ignored_pool_sum · DieRoll · mean 5.500