Python 类型错误：序列与非整数类型乘法问题及解决方案

>>> [0, 1, 2] * 3
[0, 1, 2, 0, 1, 2, 0, 1, 2]

>>> "abc" * 2
'abcabc'

import warnings

def convTemp(x=0, fro="C", to="F"):
    """
    转换温度单位。
    x: 温度数值
    fro: 原始单位 ('C', 'F', 'K')
    to: 目标单位 ('C', 'F', 'K')
    """
    if fro == "C" and to == "F":
        x = 1.8 * x + 32  # 期望 x 是一个数值
        return x
    elif fro == "C" and to == "K":
        x = x + 273.15
        return x
    elif fro == "F" and to == "C":
        x = x * (5/9) - 32
        return x # 注意：原始代码这里是 return temp，应为 return x
    elif fro == "F" and to == "K":
        x = (x * (5/9) - 32) + 273.15
        return x
    elif fro == "K" and to == "C":
        x = x - 273.15
        return x
    elif fro == "K" and to == "F":
        x = (9/5) * (x - 273.15) + 32
        return x
    else:
        if fro == to:
            warnings.warn("您的 'fro' 参数与 'to' 参数相同！")
        return x # 如果单位相同或无法转换，返回原值

# 导致错误的代码
assert convTemp([0,10,20]) == [32, 50, 68]

temperatures_c = [0, 10, 20]
converted_temperatures_f = [convTemp(t, fro="C", to="F") for t in temperatures_c]

print(f"原始摄氏温度: {temperatures_c}")
print(f"转换后的华氏温度: {converted_temperatures_f}")

# 用于断言测试的正确写法
assert [convTemp(t) for t in [0,10,20]] == [32, 50, 68]

temperatures_c = [0, 10, 20]
converted_temperatures_f = []

for t in temperatures_c:
    converted_temperatures_f.append(convTemp(t, fro="C", to="F"))

print(f"原始摄氏温度: {temperatures_c}")
print(f"转换后的华氏温度 (通过循环): {converted_temperatures_f}")

temperatures_c = [0, 10, 20]
# map 返回一个迭代器，需要转换为列表
converted_temperatures_f = list(map(convTemp, temperatures_c))

print(f"原始摄氏温度: {temperatures_c}")
print(f"转换后的华氏温度 (通过 map): {converted_temperatures_f}")

# 如果需要指定 fro 和 to 参数，可以使用 lambda 表达式或 functools.partial
converted_temperatures_f_specific = list(map(lambda t: convTemp(t, fro="C", to="F"), temperatures_c))
print(f"转换后的华氏温度 (通过 map 和 lambda): {converted_temperatures_f_specific}")

import collections.abc # 导入抽象基类来检查序列类型

def convTemp_robust(x, fro="C", to="F"):
    # 检查 x 是否为序列类型（但不是字符串，因为字符串是特殊的序列）
    if isinstance(x, collections.abc.Sequence) and not isinstance(x, str):
        # 如果是序列，则递归调用自身或使用列表推导式处理每个元素
        return [convTemp_robust(item, fro, to) for item in x]
    else:
        # 否则，按原逻辑处理单个数值
        if fro == "C" and to == "F":
            return 1.8 * x + 32
        elif fro == "C" and to == "K":
            return x + 273.15
        # ... 其他转换逻辑 ...
        elif fro == to:
            warnings.warn("您的 'fro' 参数与 'to' 参数相同！")
            return x
        return x # 默认返回 x，或抛出错误/返回 None