嵌套字典从键中查找特定值

def find_value_in_nested_dict(nested_dict, target_key):
    if isinstance(nested_dict, dict):
        for key, value in nested_dict.items():
            if key == target_key:
                return value
            result = find_value_in_nested_dict(value, target_key)
            if result is not None:
                return result
    return None

# 示例嵌套字典
nested_dict = {
    'a': 1,
    'b': {
        'c': 2,
        'd': {
            'e': 3
        }
    },
    'f': 4
}

# 查找键 'e' 的值
value = find_value_in_nested_dict(nested_dict, 'e')
print(value)  # 输出: 3

def find_value_in_nested_dict_iterative(nested_dict, target_key):
    stack = [((), nested_dict)]
    while stack:
        path, current = stack.pop()
        for key, value in current.items():
            new_path = path + (key,)
            if key == target_key:
                return new_path, value
            if isinstance(value, dict):
                stack.append((new_path, value))
    return None

# 查找键 'e' 的值
value_info = find_value_in_nested_dict_iterative(nested_dict, 'e')
if value_info:
    path, value = value_info
    print(f"Value found at path {' -> '.join(path)}: {value}")  # 输出: Value found at path b -> d -> e: 3
else:
    print("Value not found")