
在数据处理过程中,我们经常会遇到需要从多个数据源整合信息以构建一个更完整数据集的场景。例如,你可能有一个包含核心记录的列表,以及其他包含补充属性的辅助列表。目标是根据共同的标识符(如名称或地址)将这些补充属性添加到核心记录中。
假设我们有以下三个字典列表:
我们的任务是创建一个新的列表 finalList,它基于 dataList,但同时从 listA 中匹配 name 字段,并添加 original_name;从 listB 中匹配 address 字段,并添加 original_address。
原始数据示例如下:
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listA = [
{
"name": "name sample 1",
"original_name" : "original name sample 1",
},
{
"name": "name sample 2",
"original_name" : "original name sample 2",
}
]
listB = [
{
"address": "address sample 1",
"original_address" : "original address sample 1",
},
{
"address": "address sample 2",
"original_address" : "original address sample 2",
}
]
dataList = [
{
"id": "1",
"created_at": "date 1",
"name": "name sample 1",
"address": "address sample 1",
},
{
"id": "2",
"created_at": "date 2",
"name": "name sample 2",
"address": "address sample 2",
}
]期望的 finalList 结构应为:
finalList = [
{
"id": "1",
"created_at": "date 1",
"name": "name sample 1",
"original_name" : "original name sample 1",
"address": "address sample 1",
"original_address" : "original address sample 1",
},
{
"id": "2",
"created_at": "date 2",
"name": "name sample 2",
"original_name" : "original name sample 2",
"address": "address sample 2",
"original_address" : "original address sample 2",
}
]一种直观且有效的方法是利用 Python 的循环结构,遍历辅助列表,并在主列表中查找匹配项进行更新。为了避免修改原始 dataList,我们首先创建一个它的深拷贝。
from copy import deepcopy
# 原始数据定义 (与上述场景描述一致)
listA = [
{"name": "name sample 1", "original_name" : "original name sample 1"},
{"name": "name sample 2", "original_name" : "original name sample 2"}
]
listB = [
{"address": "address sample 1", "original_address" : "original address sample 1"},
{"address": "address sample 2", "original_address" : "original address sample 2"}
]
dataList = [
{"id": "1", "created_at": "date 1", "name": "name sample 1", "address": "address sample 1"},
{"id": "2", "created_at": "date 2", "name": "name sample 2", "address": "address sample 2"}
]
# 1. 创建dataList的深拷贝,避免修改原始数据
finalList = deepcopy(dataList)
# 2. 遍历listA和listB的合并结果
# 这种方式巧妙地将两个不同类型的补充数据统一处理
for entry in listA + listB:
# 3. 根据entry中存在的键(name或address)进行判断
if "name" in entry:
# 如果是来自listA的条目,则匹配name并添加original_name
for data in finalList:
if data['name'] == entry['name']:
data['original_name'] = entry['original_name']
elif "address" in entry:
# 如果是来自listB的条目,则匹配address并添加original_address
for data in finalList:
if data['address'] == entry['address']:
data['original_address'] = entry['original_address']
# 打印结果,验证原始dataList未被修改,且finalList已包含所需信息
print("原始dataList (未修改):")
print(dataList)
print("\n合并后的finalList:")
print(finalList)原始dataList (未修改):
[{'id': '1', 'created_at': 'date 1', 'name': 'name sample 1', 'address': 'address sample 1'}, {'id': '2', 'created_at': 'date 2', 'name': 'name sample 2', 'address': 'address sample 2'}]
合并后的finalList:
[{'id': '1', 'created_at': 'date 1', 'name': 'name sample 1', 'address': 'address sample 1', 'original_name': 'original name sample 1', 'original_address': 'original address sample 1'}, {'id': '2', 'created_at': 'date 2', 'name': 'name sample 2', 'address': 'address sample 2', 'original_name': 'original name sample 2', 'original_address': 'original address sample 2'}]上述方法对于小规模数据是有效且易于理解的。然而,当列表规模非常大时,嵌套循环的性能会成为瓶颈。其时间复杂度为 O(M * N),其中 M 是 listA + listB 的总长度,N 是 finalList 的长度。对于大型数据集,可以考虑以下优化策略:
将辅助列表转换为字典(哈希映射),以实现 O(1) 的平均查找时间。这将把整体时间复杂度降低到 O(M + N),因为预处理和最终遍历
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