如何对JSON数组按week_year分组并计算每周total总和？

核心逻辑所有方案通用：以week_year为唯一分组标识，遍历所有元素累加对应total值，最后输出为目标数组格式即可，不同常用技术栈的实现代码如下：

JavaScript 实现 #

用数组reduce方法是最简洁的实现：

const originData = [
    {"week_year": "49-2021","total": 6.5},
    {"week_year": "45-2021","total": 28.5},
    {"week_year": "45-2021","total": 6.5},
    {"week_year": "44-2021","total": 6.5},
    {"week_year": "46-2021","total": 14.5}
];

const groupedResult = Object.values(originData.reduce((acc, item) => {
    const weekKey = item.week_year;
    // 不存在该分组则初始化
    if (!acc[weekKey]) acc[weekKey] = { week_year: weekKey, total: 0 };
    // 累加当前值
    acc[weekKey].total += item.total;
    return acc;
}, {}));

输出的groupedResult就是分组求和后的目标数组。

Python 实现 #

原生Python实现（无第三方依赖） #

origin_data = [
    {"week_year": "49-2021","total": 6.5},
    {"week_year": "45-2021","total": 28.5},
    {"week_year": "45-2021","total": 6.5},
    {"week_year": "44-2021","total": 6.5},
    {"week_year": "46-2021","total": 14.5}
]

group_dict = {}
for item in origin_data:
    week_key = item["week_year"]
    group_dict[week_key] = group_dict.get(week_key, 0) + item["total"]

# 转换为目标结构数组
grouped_result = [{"week_year": k, "total": v} for k, v in group_dict.items()]

用Pandas实现（适合大数据量场景） #

import pandas as pd

df = pd.DataFrame(origin_data)
grouped_result = df.groupby("week_year", as_index=False)["total"].sum().to_dict("records")

SQL实现（数据存储在关系型数据库时） #

假设你的数据存在weekly_records表中，直接用分组查询即可：

SELECT week_year, SUM(total) AS total
FROM weekly_records
GROUP BY week_year;

内容的提问来源于stack exchange，提问作者rjsnavarette