From 28d0428b504f5325857c9f2a8f6c8f8d3ccc6ca9 Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Mon, 6 Mar 2023 17:49:56 +0800
Subject: [PATCH] feat: add Range function

---
 mathutil/mathutil.go              | 17 +++++++++++++++++
 mathutil/mathutil_exmaple_test.go | 18 ++++++++++++++++++
 mathutil/mathutil_test.go         | 14 ++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/mathutil/mathutil.go b/mathutil/mathutil.go
index 954f22c..0390b16 100644
--- a/mathutil/mathutil.go
+++ b/mathutil/mathutil.go
@@ -183,3 +183,20 @@ func Average[T constraints.Integer | constraints.Float](numbers ...T) T {
 	}
 	return sum / n
 }
+
+// Range creates a slice of numbers from start with specified count, element step is 1.
+// Play: todo
+func Range[T constraints.Integer | constraints.Float](start T, count int) []T {
+	size := count
+	if count < 0 {
+		size = -count
+	}
+
+	result := make([]T, size)
+
+	for i, j := 0, start; i < size; i, j = i+1, j+1 {
+		result[i] = j
+	}
+
+	return result
+}
diff --git a/mathutil/mathutil_exmaple_test.go b/mathutil/mathutil_exmaple_test.go
index 2e15ea7..1e78be6 100644
--- a/mathutil/mathutil_exmaple_test.go
+++ b/mathutil/mathutil_exmaple_test.go
@@ -185,3 +185,21 @@ func ExampleMinBy() {
 	// ab
 	//
 }
+
+func ExampleRange() {
+	result1 := Range(1, 4)
+	result2 := Range(1, -4)
+	result3 := Range(-4, 4)
+	result4 := Range(1.0, 4)
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+	fmt.Println(result4)
+
+	// Output:
+	// [1 2 3 4]
+	// [1 2 3 4]
+	// [-4 -3 -2 -1]
+	// [1 2 3 4]
+}
diff --git a/mathutil/mathutil_test.go b/mathutil/mathutil_test.go
index b7388fc..8c99a88 100644
--- a/mathutil/mathutil_test.go
+++ b/mathutil/mathutil_test.go
@@ -137,3 +137,17 @@ func TestMinBy(t *testing.T) {
 	})
 	assert.Equal("", res3)
 }
+
+func TestRange(t *testing.T) {
+	assert := internal.NewAssert(t, "Range")
+
+	result1 := Range(1, 4)
+	result2 := Range(1, -4)
+	result3 := Range(-4, 4)
+	result4 := Range(1.0, 4)
+
+	assert.Equal([]int{1, 2, 3, 4}, result1)
+	assert.Equal([]int{1, 2, 3, 4}, result2)
+	assert.Equal([]int{-4, -3, -2, -1}, result3)
+	assert.Equal([]float64{1.0, 2.0, 3.0, 4.0}, result4)
+}