From abf392117a2e62864044a17c992dfbc7b608fc62 Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Thu, 9 Feb 2023 19:25:58 +0800
Subject: [PATCH] feat: add IsAscending, Isdescending

---
 slice/slice.go              | 24 ++++++++++++++++++++++++
 slice/slice_example_test.go | 32 ++++++++++++++++++++++++++++++++
 slice/slice_test.go         | 16 ++++++++++++++++
 3 files changed, 72 insertions(+)

diff --git a/slice/slice.go b/slice/slice.go
index 04e712f..4f9c662 100644
--- a/slice/slice.go
+++ b/slice/slice.go
@@ -830,6 +830,30 @@ func Shuffle[T any](slice []T) []T {
 	return slice
 }
 
+// IsAscending checks if a slice is ascending order.
+// Play: todo
+func IsAscending[T constraints.Ordered](slice []T) bool {
+	for i := 1; i < len(slice); i++ {
+		if slice[i-1] > slice[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Isdescending checks if a slice is descending order.
+// Play: todo
+func Isdescending[T constraints.Ordered](slice []T) bool {
+	for i := 1; i < len(slice); i++ {
+		if slice[i-1] < slice[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
 // Sort sorts a slice of any ordered type(number or string), use quick sort algrithm.
 // default sort order is ascending (asc), if want descending order, set param `sortOrder` to `desc`.
 // Play: https://go.dev/play/p/V9AVjzf_4Fk
diff --git a/slice/slice_example_test.go b/slice/slice_example_test.go
index faae325..87498c9 100644
--- a/slice/slice_example_test.go
+++ b/slice/slice_example_test.go
@@ -685,6 +685,38 @@ func ExampleReverse() {
 	// [d c b a]
 }
 
+func ExampleIsAscending() {
+
+	result1 := IsAscending([]int{1, 2, 3, 4, 5})
+	result2 := IsAscending([]int{5, 4, 3, 2, 1})
+	result3 := IsAscending([]int{2, 1, 3, 4, 5})
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+
+	// Output:
+	// true
+	// false
+	// false
+}
+
+func ExampleIsdescending() {
+
+	result1 := Isdescending([]int{5, 4, 3, 2, 1})
+	result2 := Isdescending([]int{1, 2, 3, 4, 5})
+	result3 := Isdescending([]int{2, 1, 3, 4, 5})
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+
+	// Output:
+	// true
+	// false
+	// false
+}
+
 func ExampleSort() {
 	nums := []int{1, 4, 3, 2, 5}
 
diff --git a/slice/slice_test.go b/slice/slice_test.go
index 33b1d11..d911464 100644
--- a/slice/slice_test.go
+++ b/slice/slice_test.go
@@ -603,6 +603,22 @@ func TestDifferenceBy(t *testing.T) {
 	assert.Equal([]int{1, 2}, DifferenceBy(s1, s2, addOne))
 }
 
+func TestIsAscending(t *testing.T) {
+	assert := internal.NewAssert(t, "TestIsAscending")
+
+	assert.Equal(true, IsAscending([]int{1, 2, 3, 4, 5}))
+	assert.Equal(false, IsAscending([]int{5, 4, 3, 2, 1}))
+	assert.Equal(false, IsAscending([]int{2, 1, 3, 4, 5}))
+}
+
+func TestIsdescending(t *testing.T) {
+	assert := internal.NewAssert(t, "TestIsdescending")
+
+	assert.Equal(true, Isdescending([]int{5, 4, 3, 2, 1}))
+	assert.Equal(false, Isdescending([]int{1, 2, 3, 4, 5}))
+	assert.Equal(false, Isdescending([]int{2, 1, 3, 4, 5}))
+}
+
 func TestSort(t *testing.T) {
 	assert := internal.NewAssert(t, "TestSort")