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pkg/slicesx/slicesx.go

@@ -0,0 +1,50 @@
+package slicesx
+
+import (
+	"golang.org/x/exp/constraints"
+	"golang.org/x/exp/slices"
+)
+
+// Any returns true if test returns true for any of values.
+func Any[T any](values []T, test func(T) bool) bool {
+	for _, v := range values {
+		if test(v) {
+			return true
+		}
+	}
+	return false
+}
+
+// Filter filters values in place
+func Filter[T any](values []T, filter func(T) bool) []T {
+	results := values[:0]
+	for _, value := range values {
+		if filter(value) {
+			results = append(results, value)
+		}
+	}
+	return results
+}
+
+// NonSequential sorts values, and then removes elements for which test() returns true.
+// NonSequential does not re-allocate, but uses the existing slice.
+func NonSequential[T constraints.Ordered](values []T, test func(prev, current T) bool) []T {
+	if len(values) < 2 {
+		return values
+	}
+
+	// sort the values and make a results array
+	slices.Sort(values)
+	results := values[:1]
+
+	// do the filter loop
+	prev := results[0]
+	for _, current := range values[1:] {
+		if !test(prev, current) {
+			results = append(results, current)
+		}
+		prev = current
+	}
+
+	return results
+}