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+"""variables_operators_basics.py - Python 变量与运算符基础示例
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+
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+涵盖:变量定义、命名规则、赋值、类型推断、常见算术运算符、比较运算符、
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+逻辑运算符、赋值运算符、成员运算符、身份运算符,以及运算优先级说明。
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+"""
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+
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+
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+def main():
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+ # 1. 变量:用来存储数据的标识符
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+ name = "Alice"
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+ age = 18
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+ height = 1.72
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+ is_student = True
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+
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+ print("name ->", name)
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+ print("age ->", age)
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+ print("height ->", height)
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+ print("is_student ->", is_student)
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+
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+ # 2. 变量命名规则
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+ # - 只能包含字母、数字、下划线
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+ # - 不能以数字开头
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+ # - 不能使用 Python 关键字
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+ # - 建议使用 snake_case
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+ user_name = "Bob"
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+ max_score = 100
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+ print("user_name ->", user_name)
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+ print("max_score ->", max_score)
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+
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+ # 3. 多变量赋值
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+ a, b, c = 10, 20, 30
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+ print("a, b, c ->", a, b, c)
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+
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+ x = y = 100
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+ print("x == y ->", x == y)
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+
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+ # 4. 动态类型:变量不需要声明类型,赋值时自动决定类型
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+ num = 10
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+ num = "ten"
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+ print("num after reassignment ->", num)
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+
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+ # 5. 算术运算符
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+ print("5 + 3 ->", 5 + 3)
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+ print("5 - 3 ->", 5 - 3)
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+ print("5 * 3 ->", 5 * 3)
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+ print("10 / 3 ->", 10 / 3) # 浮点除法
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+ print("10 // 3 ->", 10 // 3) # 整除
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+ print("10 % 3 ->", 10 % 3) # 取余
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+ print("2 ** 3 ->", 2 ** 3) # 幂运算
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+
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+ # 6. 比较运算符
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+ print("5 > 3 ->", 5 > 3)
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+ print("5 == 3 ->", 5 == 3)
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+ print("5 != 3 ->", 5 != 3)
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+ print("5 >= 3 ->", 5 >= 3)
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+ print("5 <= 3 ->", 5 <= 3)
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+
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+ # 7. 逻辑运算符
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+ print("True and False ->", True and False)
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+ print("True or False ->", True or False)
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+ print("not True ->", not True)
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+
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+ # 8. 赋值运算符
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+ total = 10
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+ total += 5 # total = total + 5
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+ total *= 2 # total = total * 2
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+ print("total ->", total)
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+
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+ # 9. 身份运算符:判断两个对象是否为同一个对象
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+ p = [1, 2]
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+ q = p
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+ r = [1, 2]
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+ print("p is q ->", p is q)
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+ print("p is r ->", p is r)
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+
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+ # 10. 成员运算符:判断元素是否在序列里
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+ fruits = ["apple", "banana", "orange"]
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+ print("'apple' in fruits ->", 'apple' in fruits)
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+ print("'pear' not in fruits ->", 'pear' not in fruits)
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+
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+ # 11. 位运算符(进阶,了解即可)
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+ print("5 & 3 ->", 5 & 3)
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+ print("5 | 3 ->", 5 | 3)
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+ print("5 ^ 3 ->", 5 ^ 3)
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+ print("~5 ->", ~5)
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+
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+ # 12. 运算优先级(从高到低)
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+ # 一般顺序:括号 > 幂运算 > 乘除取模 > 加减 > 比较 > not > and > or
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+ result = 10 + 3 * 2 ** 2
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+ print("10 + 3 * 2 ** 2 ->", result)
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+
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+ # 13. 变量的作用
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+ # - 存储数据
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+ # - 程序中用于表达、计算、判断
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+ # - 让代码更清晰、可维护
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+
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+ # 14. 小结
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+ # Python 中变量没有固定类型,运算符用于进行计算、比较、逻辑判断和赋值。
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+ # 根据需要选择合适的运算符即可。
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+
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+
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+# if __name__ == '__main__':
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+# main()
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+
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+
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+p = [1, 2]
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+q = p
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+r = [1, 2]
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+print("p is q ->", p is q)
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+print("p is r ->", p is r)
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+print("p == r ->", p == r)
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