如何从MongoDB的嵌套数组结构中获取additionalData内的值？

以下是几种常用编程语言的实现方式：

JavaScript实现 #

1. 先将JSON字符串解析为对象，再直接访问目标属性：

// 定义JSON字符串
const jsonStr = `{    
    "producer" : "abc",
    "time" : "2023-01-02T06:30:52.004",
    "type" : "type",
    "transactionId" : "6c809bfd-563f-47d4-a2ef-4941acdc09bf",   
    "additionalData" : {
        "key" : "key",
        "value" : [ 5363, 5355 ]
    }
}`;

// 解析为对象
const data = JSON.parse(jsonStr);

// 获取additionalData整体内容
const additionalData = data.additionalData;
console.log(additionalData); // 输出：{ key: 'key', value: [ 5363, 5355 ] }

// 单独获取additionalData内的key或value
const key = data.additionalData.key;
const valueArray = data.additionalData.value;
console.log(key); // 输出：key
console.log(valueArray); // 输出：[ 5363, 5355 ]

Python实现 #

import json

# 定义JSON字符串
json_str = '''{    
    "producer" : "abc",
    "time" : "2023-01-02T06:30:52.004",
    "type" : "type",
    "transactionId" : "6c809bfd-563f-47d4-a2ef-4941acdc09bf",   
    "additionalData" : {
        "key" : "key",
        "value" : [ 5363, 5355 ]
    }
}'''

# 解析为字典
data = json.loads(json_str)

# 获取additionalData整体内容
additional_data = data['additionalData']
print(additional_data) # 输出：{'key': 'key', 'value': [5363, 5355]}

# 单独获取additionalData内的key或value
key_val = data['additionalData']['key']
value_arr = data['additionalData']['value']
print(key_val) # 输出：key
print(value_arr) # 输出：[5363, 5355]

内容的提问来源于stack exchange，提问作者Azim Uddin