print("--- AI训练常用工具 ---")          # 增加行1：打印标题
tools = ["TensorFlow", "PyTorch", "Keras"]
print("初始工具列表:",   tools   )
print("当前工具数量:",   len(tools)      )       # 增加行2：打印列表长度
print("\n--- 添加新工具 ---")
new_tools = ["Scikit-learn", "MXNet"]
for tool in new_tools:
    if tool not in tools:
        tools.  append      (tool)
    else:      
        print(f"工具 '{tool}' 已存在，跳过添加")
 
print("\n更新后的工具列表:",      tools    )  
print("\n更新后的工具列表数量:",  len(tools )    )