如何将字典作为另一个值附加到现有字典键

# 步骤1：定义要附加的字典和要附加到的字典键
existing_dict = {
    "key1": "value1",
    "key2": {
        "nested_key1": "nested_value1",
        "nested_key2": "nested_value2"
    }
}

existing_key = "key2"
new_dict = {
    "nested_key3": "nested_value3",
    "nested_key4": "nested_value4"
}

# 步骤2：检查现有字典中的键
if existing_key in existing_dict:
    # 步骤3：如果键已经存在且对应值为字典，直接将新字典附加到该字典中
    if isinstance(existing_dict[existing_key], dict):
        existing_dict[existing_key].update(new_dict)
    else:
        # 步骤5：如果对应值不是字典，则创建一个新的字典，将原始值和新字典添加到新字典中
        existing_dict[existing_key] = {
            "existing_value": existing_dict[existing_key],
            **new_dict
        }
else:
    # 步骤4：如果键不存在，直接将键值对添加到现有字典中
    existing_dict[existing_key] = new_dict

print(existing_dict)

{
    "key1": "value1",
    "key2": {
        "nested_key1": "nested_value1",
        "nested_key2": "nested_value2",
        "nested_key3": "nested_value3",
        "nested_key4": "nested_value4"
    }
}