Refactor Strip (already).

Stripping cards from the Hand will also be useful, so I pulled the logic of Strip out into arrayutil (more efficiently, too) and rewrote deck.Strip to use it.

cardsim/deck.go

@@ -264,9 +264,18 @@ func (d *Deck[C]) ShuffleTop(frac float64) error {
 	return d.ShuffleRange(0.0, frac)
 }
 
-// Shufflebottom uses ShuffleRange to shuffle the bottom frac (between 0.0 and
+// ShuffleBottom uses ShuffleRange to shuffle the bottom frac (between 0.0 and
 // 1.0) of the deck. See ShuffleRange and ShufflePart for information on
 // rounding and warnings.
 func (d *Deck[C]) ShuffleBottom(frac float64) error {
 	return d.ShuffleRange(frac, 1.0)
 }
+
+// Strip removes all cards from the deck where shouldRemove returns true.
+// shouldRemove is provided with each card in the deck and its index.
+// It returns how many cards were stripped from the deck.
+func (d *Deck[C]) Strip(shouldRemove func(idx int, c Card[C]) bool) int {
+	origLen := d.Len()
+	d.cards = Strip(d.cards, shouldRemove)
+	return origLen - d.Len()
+}

cardsim/sliceutil.go

@@ -126,3 +126,22 @@ func ShufflePart[T any](slice []T, r *rand.Rand, loc, n int) {
 	}
 	ShuffleAll(slice[loc:loc+n], r)
 }
+
+// Strip iterates T, removing any element for which removeWhen returns true
+// (when provided the index of the element and the element itself as arguments).
+// It returns the stripped slice.
+func Strip[T any](slice []T, removeWhen func(idx int, t T) bool) []T {
+	if len(slice) == 0 {
+		return nil
+	}
+	to := 0
+	for from, e := range slice {
+		if !removeWhen(from, e) {
+			if to != from {
+				slice[to] = slice[from]
+			}
+			to++
+		}
+	}
+	return slice[:to]
+}