如何递归统计任意嵌套结构中含指定key的对象总数？

要统计任意嵌套结构中包含指定key的对象数量，最直接的方式是递归遍历整个数据结构，对每个元素进行判断：

实现思路 #

1. 定义递归函数，接收待遍历的数据和目标key两个参数
2. 初始化计数器为0
3. 如果当前元素是字典（JSON对象）：
   • 检查是否包含目标key，是则计数器+1
   • 递归遍历字典的所有值，累加计数
4. 如果当前元素是列表/元组（JSON数组）：
   • 递归遍历列表中的每个元素，累加计数
5. 其他类型（如字符串、数字等）直接返回0，不处理

Python 代码实现 #

def count_objects_with_key(data, target_key):
    count = 0
    # 处理字典类型（JSON对象）
    if isinstance(data, dict):
        # 检查当前字典是否包含目标key
        if target_key in data:
            count += 1
        # 递归遍历字典的所有值
        for value in data.values():
            count += count_objects_with_key(value, target_key)
    # 处理列表/元组类型（JSON数组）
    elif isinstance(data, (list, tuple)):
        for item in data:
            count += count_objects_with_key(item, target_key)
    # 其他数据类型直接跳过
    return count

测试示例 #

用你提供的两组数据测试：

测试第一组数据 #

data1 = {"coins_series": [{"series": 1, "coins": [{"_id": "65c8c78845d911984d98f6be", "currency": "EUR", "reverse_id": "SVN200701001REG", "obverse_id": ["EUR199901001FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 0.01, "diameter": 16.25, "thickness": 1.67, "weight": 2.3}, {"_id": "65c8c78845d911984d98f6bf", "currency": "EUR", "reverse_id": "SVN200701002REG", "obverse_id": ["EUR199901002FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 0.02, "diameter": 18.75, "thickness": 1.67, "weight": 3.06}, {"_id": "65c8c78845d911984d98f6c0", "currency": "EUR", "reverse_id": "SVN200701005REG", "obverse_id": ["EUR199901005FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 0.05, "diameter": 21.25, "thickness": 1.67, "weight": 3.92}, {"_id": "65c8c78845d911984d98f6c1", "currency": "EUR", "reverse_id": "SVN200701010REG", "obverse_id": ["EUR200702010FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 0.1, "diameter": 19.75, "thickness": 1.93, "weight": 4.1}, {"_id": "65c8c78845d911984d98f6c2", "currency": "EUR", "reverse_id": "SVN200701020REG", "obverse_id": ["EUR200702020FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 0.2, "diameter": 22.25, "thickness": 2.14, "weight": 5.74}, {"_id": "65c8c78845d911984d98f6c3", "currency": "EUR", "reverse_id": "SVN200701050REG", "obverse_id": ["EUR200702050FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 0.5, "diameter": 24.25, "thickness": 2.38, "weight": 7.8}, {"_id": "65c8c78845d911984d98f6c4", "currency": "EUR", "reverse_id": "SVN200701100REG", "obverse_id": ["EUR200702100FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 1, "diameter": 23.25, "thickness": 2.33, "weight": 7.5}, {"_id": "65c8c78845d911984d98f6c5", "currency": "EUR", "reverse_id": "SVN200701200REG", "obverse_id": ["EUR200702200FRO"], "country": "SVN", "commemorative": False, "series": 1, "min_year": 2007, "denomination": 2, "diameter": 25.75, "thickness": 2.2, "weight": 8.5}]}], "country": "SVN"}

print(count_objects_with_key(data1, "commemorative"))  # 输出：8

测试第二组数据 #

data2 = {"series": 2, "coins": [{"_id": "65c8c78845d911984d98f724", "currency": "EUR", "reverse_id": "VAT200502001REG", "obverse_id": ["EUR199901001FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 0.01, "diameter": 16.25, "thickness": 1.67, "weight": 2.3}, {"_id": "65c8c78845d911984d98f725", "currency": "EUR", "reverse_id": "VAT200502002REG", "obverse_id": ["EUR199901002FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 0.02, "diameter": 18.75, "thickness": 1.67, "weight": 3.06}, {"_id": "65c8c78845d911984d98f726", "currency": "EUR", "reverse_id": "VAT200502005REG", "obverse_id": ["EUR199901005FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 0.05, "diameter": 21.25, "thickness": 1.67, "weight": 3.92}, {"_id": "65c8c78845d911984d98f727", "currency": "EUR", "reverse_id": "VAT200502010REG", "obverse_id": ["EUR199901010FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 0.1, "diameter": 19.75, "thickness": 1.93, "weight": 4.1}, {"_id": "65c8c78845d911984d98f728", "currency": "EUR", "reverse_id": "VAT200502020REG", "obverse_id": ["EUR199901020FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 0.2, "diameter": 22.25, "thickness": 2.14, "weight": 5.74}, {"_id": "65c8c78845d911984d98f729", "currency": "EUR", "reverse_id": "VAT200502050REG", "obverse_id": ["EUR199901050FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 0.5, "diameter": 24.25, "thickness": 2.38, "weight": 7.8}, {"_id": "65c8c78845d911984d98f72a", "currency": "EUR", "reverse_id": "VAT200502100REG", "obverse_id": ["EUR199901100FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 1, "diameter": 23.25, "thickness": 2.33, "weight": 7.5}, {"_id": "65c8c78845d911984d98f72b", "currency": "EUR", "reverse_id": "VAT200502200REG", "obverse_id": ["EUR199901200FRO"], "country": "VAT", "commemorative": False, "series": 2, "min_year": 2005, "max_year": 2005, "denomination": 2, "diameter": 25.75, "thickness": 2.2, "weight": 8.5}]}

print(count_objects_with_key(data2, "commemorative"))  # 输出：8

注意事项 #

• 该函数会遍历所有嵌套层级，无论数据结构多复杂都能覆盖
• 如果数据存在循环引用（如字典引用自身），会导致递归无限循环，这种场景需要额外添加循环检测逻辑
• 兼容常见JSON数据类型：对象（dict）、数组（list/tuple）、字符串、数字、布尔值、null（None）

内容的提问来源于stack exchange，提问作者Klak031