javascript - js 一维数组查询和数值相加
本文介绍了javascript - js 一维数组查询和数值相加的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
问 题
1.判断 var uid ="5744242bc4c971005d5ff04e" 是否存在数组中,php有 in_array() 函数,js有比较方便的吗?
2.指定的uid 数组中的数值相加。
有没有不通过遍历的方式得到结果或者最简便的方式?
[
{
"uid": "5744242bc4c971005d5ff04e",
"num": 40,
"time": 1464150797000
},
{
"uid": "5744242bc4c971005d5ff04e",
"num": 12,
"time": 1464251797000
},
{
"uid": "574424e5df0eea0063adefc6",
"num": 10,
"time": 1464152873000
}
]
解决方案
题主表意不明。
如果是一维数组的话:
var sum = function (input, uid) {
return input.filter(function (i) { return i.uid === uid; }).reduce(function (f, s) { return f.num + s.num; });
};
sum([{"uid":"5744242bc4c971005d5ff04e","num":40,"time":1464150797000},{"uid":"5744242bc4c971005d5ff04e","num":12,"time":1464251797000},{"uid":"574424e5df0eea0063adefc6","num":10,"time":1464152873000}], '5744242bc4c971005d5ff04e');
如果是要按照题目中的二维数组,对于出现了指定 uid 的子数组分别进行求和的话:
var sum = function (input, uid) {
return input.filter(function (i) { return i.some(function (s) { return s.uid === uid; }); }).map(function (i) { return i.reduce(function (f, s) { return f + s.num; }, 0); });
};
sum([[{"uid":"5744242bc4c971005d5ff04e","num":40,"time":1464150797000}],[{"uid":"5744242bc4c971005d5ff04e","num":12,"time":1464251797000}],[{"uid":"574424e5df0eea0063adefc6","num":10,"time":1464152873000}]], '5744242bc4c971005d5ff04e');
这篇关于javascript - js 一维数组查询和数值相加的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文