如何修复此错误"Encoders要求其输入是统一的字符串或数字。Got ['float'，'str']“

def preprocess_data(data):
    if isinstance(data, float):
        return str(data)
    elif isinstance(data, str):
        return data
    else:
        raise ValueError("Unsupported data type")

# 示例数据
data = [3.14, "hello", 2.71]

# 预处理数据
processed_data = [preprocess_data(item) for item in data]
print(processed_data)  # 输出: ['3.14', 'hello', '2.71']

class CustomEncoder:
    def encode(self, data):
        if isinstance(data, float):
            return str(data)
        elif isinstance(data, str):
            return data
        else:
            raise ValueError("Unsupported data type")

# 示例数据
data = [3.14, "hello", 2.71]

# 创建编码器实例
encoder = CustomEncoder()

# 编码数据
encoded_data = [encoder.encode(item) for item in data]
print(encoded_data)  # 输出: ['3.14', 'hello', '2.71']

# 假设数据源是一个字典列表
data_source = [
    {"value": 3.14},
    {"value": "hello"},
    {"value": 2.71}
]

# 统一转换为字符串
uniform_data = [str(item["value"]) for item in data_source]
print(uniform_data)  # 输出: ['3.14', 'hello', '2.71']