From 4b84359c0e9aa0aa92aba4aea74d29ee979b28a3 Mon Sep 17 00:00:00 2001
From: esafonov <esafonov@ozon.ru>
Date: Mon, 27 Nov 2023 02:20:35 +0700
Subject: [PATCH] slice

---
 collections/slice/slice.go      | 13 +++++++++
 collections/slice/slice_test.go | 52 +++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/collections/slice/slice.go b/collections/slice/slice.go
index 28a705d..fb21a5d 100644
--- a/collections/slice/slice.go
+++ b/collections/slice/slice.go
@@ -728,3 +728,16 @@ func SortDesc[T constraints.Ordered](s []T) {
 func FitIndex[T any](index int, s []T) int {
 	return math.MustBetween(index, 0, len(s)-1)
 }
+
+// Last returns last element. It panics if slice has zero length.
+func Last[T constraints.Ordered](s []T) T {
+	return s[len(s)-1]
+}
+
+// LastExists returns last element.
+func LastExists[T constraints.Ordered](s []T) (element T, exists bool) {
+	if len(s) == 0 {
+		return ptr.Zero[T](), false
+	}
+	return s[len(s)-1], true
+}
diff --git a/collections/slice/slice_test.go b/collections/slice/slice_test.go
index 60ad88a..7a3a599 100644
--- a/collections/slice/slice_test.go
+++ b/collections/slice/slice_test.go
@@ -892,3 +892,55 @@ func ExampleFitIndex() {
 	// 1
 	// -1
 }
+
+func ExampleLast() {
+	fmt.Println(Last([]int{10, 20, 30}))
+
+	// Output:
+	// 30
+}
+
+func TestLast_Panic(t *testing.T) {
+	t.Parallel()
+	for i, s := range [][]int{nil, {}} {
+		s := s
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			t.Parallel()
+			defer func() {
+				if r := recover(); r == nil {
+					t.Error("must panic")
+				}
+			}()
+			Last(s)
+		})
+	}
+}
+
+func ExampleLastExists() {
+	fmt.Println(LastExists([]int{10, 20, 30}))
+	fmt.Println(LastExists([]int{}))
+	fmt.Println(LastExists[int](nil))
+
+	// Output:
+	// 30 true
+	// 0 false
+	// 0 false
+}
+
+func ExampleSort() {
+	s := []int{10, 120, 30}
+	Sort(s)
+	fmt.Println(s)
+
+	// Output:
+	// [10 30 120]
+}
+
+func ExampleSortDesc() {
+	s := []int{10, 120, 30}
+	SortDesc(s)
+	fmt.Println(s)
+
+	// Output:
+	// [10 30 120]
+}