如何在现有字典dict_sample外层添加historical列表层级？

原字典结构 #

dict_sample = {
    'close': {'01/01/2022': 70327.6216, '02/01/2022': 69699.74376000001, '03/01/2022': 68400.97064, '04/01/2022': 67238.73537000001, '05/01/2022': 63901.21185000001, '06/01/2022': 63857.56575, '07/01/2022': 61243.99047, '08/01/2022': 61428.6952},
    'high': {'01/01/2022': 70592.20832, '02/01/2022': 70632.42668, '03/01/2022': 70059.4992, '04/01/2022': 69685.67126, '05/01/2022': 69189.04710000001, '06/01/2022': 64857.41691000001, '07/01/2022': 63574.54257, '08/01/2022': 62360.916040000004},
    'low': {'01/01/2022': 68087.621, '02/01/2022': 68825.25224, '03/01/2022': 67331.1328, '04/01/2022': 66893.72049, '05/01/2022': 62590.39965, '06/01/2022': 62944.24587, '07/01/2022': 60158.021, '08/01/2022': 59810.57563},
    'open': {'01/01/2022': 68087.621, '02/01/2022': 70328.65284, '03/01/2022': 69673.37348000001, '04/01/2022': 68116.52833, '05/01/2022': 67443.40665, '06/01/2022': 64352.60172, '07/01/2022': 63530.61439, '08/01/2022': 61250.77133},
    'volume': {'01/01/2022': 31239, '02/01/2022': 27020, '03/01/2022': 41062, '04/01/2022': 55589, '05/01/2022': 83744, '06/01/2022': 63076, '07/01/2022': 88358, '08/01/2022': 52544}
}

需求 #

需要创建new_dict_sample，将dict_sample包裹在名为historical的列表结构中，最终格式如下：

{
    'historical': [
        {
            'close': {'01/01/2022': 70327.6216, '02/01/2022': 69699.74376000001, '03/01/2022': 68400.97064, '04/01/2022': 67238.73537000001, '05/01/2022': 63901.21185000001, '06/01/2022': 63857.56575, '07/01/2022': 61243.99047, '08/01/2022': 61428.6952},
            'high': {'01/01/2022': 70592.20832, '02/01/2022': 70632.42668, '03/01/2022': 70059.4992, '04/01/2022': 69685.67126, '05/01/2022': 69189.04710000001, '06/01/2022': 64857.41691000001, '07/01/2022': 63574.54257, '08/01/2022': 62360.916040000004},
            'low': {'01/01/2022': 68087.621, '02/01/2022': 68825.25224, '03/01/2022': 67331.1328, '04/01/2022': 66893.72049, '05/01/2022': 62590.39965, '06/01/2022': 62944.24587, '07/01/2022': 60158.021, '08/01/2022': 59810.57563},
            'open': {'01/01/2022': 68087.621, '02/01/2022': 70328.65284, '03/01/2022': 69673.37348000001, '04/01/2022': 68116.52833, '05/01/2022': 67443.40665, '06/01/2022': 64352.60172, '07/01/2022': 63530.61439, '08/01/2022': 61250.77133},
            'volume': {'01/01/2022': 31239, '02/01/2022': 27020, '03/01/2022': 41062, '04/01/2022': 55589, '05/01/2022': 83744, '06/01/2022': 63076, '07/01/2022': 88358, '08/01/2022': 52544}
        }
    ]
}

尝试的错误代码 #

new_dict_sample = [{k : val[x] for k, val in dict_sample.items()} for x in range(2)]

错误原因分析 #

1. 代码中val[x]的写法完全错误：val是dict_sample里的子字典（比如close对应的日期-数值字典），其键是日期字符串，不存在整数索引x（0或1），会直接触发KeyError。
2. 整体结构偏离需求：需求是生成一个外层字典（键为historical），而你的代码生成的是一个列表，内部字典的结构也和目标完全不符。

正确实现代码 #

直接构造目标结构即可，无需复杂推导：

new_dict_sample = {'historical': [dict_sample]}

如果需要避免后续修改dict_sample影响new_dict_sample中的内容，可以使用深拷贝：

import copy
new_dict_sample = {'historical': [copy.deepcopy(dict_sample)]}

内容的提问来源于stack exchange，提问作者leolapa