diff --git a/codes/csharp/chapter_array_and_linkedlist/array.cs b/codes/csharp/chapter_array_and_linkedlist/array.cs
index 97a37f04..92221965 100644
--- a/codes/csharp/chapter_array_and_linkedlist/array.cs
+++ b/codes/csharp/chapter_array_and_linkedlist/array.cs
@@ -11,8 +11,10 @@ namespace hello_algo.chapter_array_and_linkedlist
         /* 随机返回一个数组元素 */
         public static int RandomAccess(int[] nums)
         {
-            Random random = new();
+            Random random=new();
+            // 在区间 [0, nums.Length) 中随机抽取一个数字
             int randomIndex = random.Next(nums.Length);
+            // 获取并返回随机元素
             int randomNum = nums[randomIndex];
             return randomNum;
         }
diff --git a/codes/python/chapter_array_and_linkedlist/array.py b/codes/python/chapter_array_and_linkedlist/array.py
index 8933fb48..e5979b51 100644
--- a/codes/python/chapter_array_and_linkedlist/array.py
+++ b/codes/python/chapter_array_and_linkedlist/array.py
@@ -10,8 +10,8 @@ from include import *
 
 """ 随机访问元素 """
 def randomAccess(nums):
-    # 在区间 [0, len(nums)) 中随机抽取一个数字
-    random_index = random.randint(0, len(nums))
+    # 在区间 [0, len(nums)-1] 中随机抽取一个数字
+    random_index = random.randint(0, len(nums) - 1)
     # 获取并返回随机元素
     random_num = nums[random_index]
     return random_num
diff --git a/docs/chapter_array_and_linkedlist/array.md b/docs/chapter_array_and_linkedlist/array.md
index b18a0bbd..de25369a 100644
--- a/docs/chapter_array_and_linkedlist/array.md
+++ b/docs/chapter_array_and_linkedlist/array.md
@@ -111,6 +111,7 @@ elementAddr = firtstElementAddr + elementLength * elementIndex
     ```java title="array.java"
     /* 随机返回一个数组元素 */
     int randomAccess(int[] nums) {
+        // 在区间 [0, nums.length) 中随机抽取一个数字
         int randomIndex = ThreadLocalRandom.current().
                           nextInt(0, nums.length);
         int randomNum = nums[randomIndex];
@@ -136,8 +137,8 @@ elementAddr = firtstElementAddr + elementLength * elementIndex
     ```python title="array.py"
     """ 随机访问元素 """
     def randomAccess(nums):
-        # 在区间 [0, len(nums)) 中随机抽取一个数字
-        random_index = random.randint(0, len(nums)-1)
+        # 在区间 [0, len(nums)-1] 中随机抽取一个数字
+        random_index = random.randint(0, len(nums) - 1)
         # 获取并返回随机元素
         random_num = nums[random_index]
         return random_num
@@ -195,7 +196,9 @@ elementAddr = firtstElementAddr + elementLength * elementIndex
     int RandomAccess(int[] nums)
     {
         Random random=new();
+        // 在区间 [0, nums.Length) 中随机抽取一个数字
         int randomIndex = random.Next(nums.Length);
+        // 获取并返回随机元素
         int randomNum = nums[randomIndex];
         return randomNum;
     }