From 74402612180e4ea792c456254e95f54fa19251e9 Mon Sep 17 00:00:00 2001
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 <2509165033@student.example.com>
Date: Tue, 21 Apr 2026 11:25:29 +0800
Subject: [PATCH] =?UTF-8?q?=E4=B8=8A=E4=BC=A0=E6=96=87=E4=BB=B6=E8=87=B3?=
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---
 ljh.py | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 ljh.py

diff --git a/ljh.py b/ljh.py
new file mode 100644
index 0000000..d0c4028
--- /dev/null
+++ b/ljh.py
@@ -0,0 +1,67 @@
+
+print("题目1 ")
+
+hello1 = "Hello"  
+hello2 = 'Hello'  
+print("双引号表示:", hello1)
+print("单引号表示:", hello2)
+
+
+print("\n1. 'Hello' 每个字符的ASCII码:")
+for c in hello1:
+    print(f"字符 '{c}' → ASCII: {ord(c)}")
+
+
+print("\n2. 验证ASCII码65对应的字符:")
+print(f"chr(65) → {chr(65)}")
+
+
+
+import math
+
+
+print("\n题目3")
+A = [3, 4]
+B = [1, 2]
+
+
+A_plus_B = [A[0] + B[0], A[1] + B[1]]
+print(f"1. A + B = {A_plus_B}")
+
+
+two_times_A = [2 * A[0], 2 * A[1]]
+print(f"2. 2 × A = {two_times_A}")
+
+
+len_A = math.sqrt(A[0] ** 2 + A[1] ** 2)
+print(f"3. 向量A的长度 = {len_A}")
+
+
+
+print("\n题目4")
+A3 = [1, 2, 3]
+B3 = [4, 5, 6]
+
+
+dot_product = A3[0]*B3[0] + A3[1]*B3[1] + A3[2]*B3[2]
+print(f"1. 点积A·B = {dot_product}")
+
+
+def cosine_similarity(a, b):
+    
+    dot = sum(x*y for x,y in zip(a,b))
+    
+    norm_a = math.sqrt(sum(x*x for x in a))
+    norm_b = math.sqrt(sum(x*x for x in b))
+    
+    return dot / (norm_a * norm_b)
+
+cos_sim = cosine_similarity(A3, B3)
+print(f"2. 余弦相似度 = {cos_sim:.4f}")
+
+
+A_test = [1, 0]
+B_test = [0, 1]
+cos_sim_test = cosine_similarity(A_test, B_test)
+print(f"3. A=[1,0], B=[0,1]的余弦相似度 = {cos_sim_test}")
+print("原因：两个向量正交（垂直），方向完全不同，所以余弦相似度为0")
\ No newline at end of file