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对象列表中匹配属性的汇总属性

lodash javascript

-1

jcgh582 · 技术社区 · 5 年前

[{symbol: "SYM", value: 1}, {symbol: "SYM", value: 1}, {symbol: "DOG", value: 2}]

我该怎么减少

[{symbol: "SYM", value: 2}, {symbol: "DOG", value: 2}]

一、 e.总结匹配符号的值

3 回复 | 直到 5 年前

Dhananjai Pai 5 年前

let arr = [{symbol: "SYM", value: 1}, {symbol: "SYM", value: 1}, {symbol: "DOG", value: 2}];
valMap = arr.reduce((acc,val) => {
    if(!acc[val.symbol]) acc[val.symbol]=val.value;
    else acc[val.symbol] += val.value;
    return acc;
} ,{});
const result = Object.keys(valMap).map(key => ({symbol:key, value:valMap[key]}));

Ori Drori 5 年前

你可以用洛达斯的 _.groupBy() 和 _.sumBy()

const fn = _.flow(
  arr => _.groupBy(arr, 'symbol'),
  groups => _.map(groups, g => 
    _.assign({}, _.head(g), { value: _.sumBy(g, 'value') })
  )
);

const arr = [{symbol: "SYM", value: 1}, {symbol: "SYM", value: 1}, {symbol: "DOG", value: 2}]

const result = fn(arr);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Code Maniac 5 年前

你可以用 reduce

let obj = [{symbol: "SYM", value: 1}, {symbol: "SYM", value: 1}, {symbol: "DOG", value: 2}]

let op = obj.reduce((out,inp)=>{
  if(out[inp.symbol]){
    out[inp.symbol].value+= inp.value
  } else {
    out[inp.symbol] = inp
  }
  return out
},{})


console.log(Object.values(op))