条件语句 #

def main():
    let age = 20
    
    if age >= 18:
        print("成年人")

main()

def main():
    let age = 15
    
    if age >= 18:
        print("成年人")
    else:
        print("未成年人")

main()

def main():
    let score = 85
    
    if score >= 90:
        print("优秀")
    elif score >= 80:
        print("良好")
    elif score >= 70:
        print("中等")
    elif score >= 60:
        print("及格")
    else:
        print("不及格")

main()

def main():
    let a = 10
    let b = 20
    
    if a < b:
        print("a小于b")
    
    if a <= b:
        print("a小于等于b")
    
    if a == b:
        print("a等于b")
    
    if a != b:
        print("a不等于b")

main()

def main():
    let age = 25
    let has_license = True
    
    if age >= 18 and has_license:
        print("可以驾驶")
    
    if age < 18 or not has_license:
        print("不能驾驶")

main()

def main():
    let fruits = ["apple", "banana", "orange"]
    let fruit = "apple"
    
    if fruit in fruits:
        print(f"{fruit} 在列表中")
    
    if "grape" not in fruits:
        print("葡萄不在列表中")

main()

def main():
    let a = None
    let b = "Hello"
    
    if a is None:
        print("a是None")
    
    if b is not None:
        print("b不是None")

main()

def main():
    let age = 25
    let has_id = True
    
    if age >= 18:
        if has_id:
            print("可以进入")
        else:
            print("需要身份证")
    else:
        print("未成年人禁止进入")

main()

def main():
    let age = 25
    let has_id = True
    
    if age < 18:
        print("未成年人禁止进入")
    elif not has_id:
        print("需要身份证")
    else:
        print("可以进入")

main()

def main():
    let age = 20
    let status = "成年" if age >= 18 else "未成年"
    print(status)

main()

def main():
    let score = 85
    let grade = "A" if score >= 90 else "B" if score >= 80 else "C"
    print(grade)

main()

def main():
    let numbers = [1, 2, 3, 4, 5]
    
    for num in numbers:
        let desc = "偶数" if num % 2 == 0 else "奇数"
        print(f"{num}是{desc}")

main()

def main():
    let value = 2
    
    match value:
        case 1:
            print("一")
        case 2:
            print("二")
        case 3:
            print("三")
        case _:
            print("其他")

main()

def main():
    let value = 5
    
    match value:
        case 1 | 2 | 3:
            print("小数字")
        case 4 | 5 | 6:
            print("中等数字")
        case _:
            print("其他")

main()

def main():
    let score = 85
    
    match score:
        case s if s >= 90:
            print("优秀")
        case s if s >= 80:
            print("良好")
        case s if s >= 60:
            print("及格")
        case _:
            print("不及格")

main()

def main():
    let value: Variant = 42
    
    match value:
        case Int(x):
            print(f"整数: {x}")
        case Float(x):
            print(f"浮点数: {x}")
        case String(x):
            print(f"字符串: {x}")

main()

def main():
    let is_valid = True
    
    if is_valid:
        print("有效")

main()

def process(value: Int) -> String:
    if value < 0:
        return "无效"
    
    if value == 0:
        return "零"
    
    return "正数"

def main():
    print(process(-1))
    print(process(0))
    print(process(10))

main()

def main():
    let operation = "add"
    let a = 10
    let b = 5
    
    let operations = {
        "add": lambda x, y: x + y,
        "sub": lambda x, y: x - y,
        "mul": lambda x, y: x * y,
    }
    
    if operation in operations:
        let result = operations[operation](a, b)
        print(result)

main()

def main():
    let a = 10
    let b = 20
    
    if a > 5:
        if b > 25:
            print("条件1")
    else:
        print("条件2")

main()

def main():
    let x = 15
    
    if 10 < x < 20:
        print("x在10到20之间")

main()

def main():
    let a = 0
    
    if a != 0 and 10 / a > 1:
        print("不会执行")

main()