feat: add Max, Min, and Average function

lancetconstraints/constraints.go

@@ -11,3 +11,8 @@ type Comparator interface {
 	// Descending order: should return 1 -> v1 < v2, 0 -> v1 = v2, -1 -> v1 > v2
 	Compare(v1, v2 any) int
 }
+
+// Number contains all types of number and uintptr, used for generics constraint
+type Number interface {
+	int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64 | uintptr | float32 | float64
+}

mathutil/mathutil.go

@@ -9,6 +9,8 @@ import (
 	"math"
 	"strconv"
 	"strings"
+
+	"github.com/duke-git/lancet/v2/lancetconstraints"
 )
 
 // Exponent calculate x^n
@@ -90,3 +92,40 @@ func TruncRound(x float64, n int) float64 {
 	res, _ := strconv.ParseFloat(newFloat, 64)
 	return res
 }
+
+// Max return max value of params
+func Max[T lancetconstraints.Number](numbers ...T) T {
+	max := numbers[0]
+
+	for _, v := range numbers {
+		if max < v {
+			max = v
+		}
+	}
+
+	return max
+}
+
+// Min return min value of params
+func Min[T lancetconstraints.Number](numbers ...T) T {
+	min := numbers[0]
+
+	for _, v := range numbers {
+		if min > v {
+			min = v
+		}
+	}
+
+	return min
+}
+
+// Average return average value of params
+func Average[T lancetconstraints.Number](numbers ...T) T {
+	var sum T
+	n := T(len(numbers))
+
+	for _, v := range numbers {
+		sum += v
+	}
+	return sum / n
+}

mathutil/mathutil_test.go

@@ -70,3 +70,13 @@ func TestTruncRound(t *testing.T) {
 	assert.Equal(TruncRound(0.125, 3), float64(0.125))
 	assert.Equal(TruncRound(33.33333, 2), float64(33.33))
 }
+
+func TestAverage(t *testing.T) {
+	assert := internal.NewAssert(t, "TestAverage")
+
+	assert.Equal(Average(0, 0), 0)
+	assert.Equal(Average(1, 1), 1)
+	avg := Average(1.2, 1.4)
+	t.Log(avg)
+	assert.Equal(1.3, RoundToFloat(avg, 1))
+}