问题描述
我有一系列的联系卡,其中包含用户的姓名和地址等。我想做的是创建另一个数组,该数组删除所有重复的地址(即同一家庭中的人),并创建一个将两者结合的名称。例如:
{flatNum: 1,Name: "ken"},{flatNum: 1,Name: "bob"},{flatNum: 2,Name: "emma"}
将成为:
{flatNum: 1,Name: "ken & bob"},Name: "emma"}
我知道如何使用长的for
循环类型的东西来实现此目的,但是希望找到一种更简洁的方法。我假设reduce
是关键并且一直在玩耍。目前得到这个:
let contactCardsComb = contactCards.reduce(function(a,b){
if (a.flatNum == b.flatNum){
return a.Name = a.Name+b.Name;
}
});
这显然是错误的,但是任何指针都很好
解决方法
您可以按flatNum
分组并从对象中获取值。
const
data = [{ flatNum: 1,Name: "ken" },{ flatNum: 1,Name: "bob" },{ flatNum: 2,Name: "emma" }],result = Object.values(data.reduce((r,{ flatNum,Name }) => {
if (r[flatNum]) r[flatNum].Name += ' & ' + Name;
else r[flatNum] = { flatNum,Name };
return r;
},{}));
console.log(result);
,
这可以通过使用# 0
print(next(d['variable0']))
# 0
print(next(d['variable1']))
# 1
print(next(d['variable1']))
库轻松实现,
lodash
let contactCards = [
{flatNum: 1,Name: "ken"},{flatNum: 1,Name: "bob"},{flatNum: 2,Name: "emma"},Name: "april"},Name: "june"}
];
let tempGroup = _.groupBy(contactCards,contact => {
return contact.flatNum;
});
console.log('tempGroup :',tempGroup);
let contactCardsComb = Object
.values(tempGroup)
.map( e => e.reduce( (a,b) =>
({...a,Name: `${ a.Name } & ${ b.Name }` })
));
console.log('result : ',contactCardsComb);
.as-console-wrapper { min-height: 100%!important; top: 0; }
//香草方法如下
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash-compat/3.10.2/lodash.min.js"></script>
或者我们可以将其包装如下
let flatNums = Array.from(new Set(contactCards.map( e => e.flatNum)))
let groupedContactCards = flatNums
.map( e => contactCards
.filter(contact => contact.flatNum === e))
let reducedContactCards = groupedContactCards
.map( e => e
.reduce((a,b) => ({...a,Name:`${a.Name} & ${b.Name}`})))
console.log(reducedContactCards)
,
我将OP的Q.当作一次机会来证明抽象但(高度)可配置的reduce任务在短时间内(不到一分钟,这里是OP的问题)适合于乍看之下的各种问题由于环境不同以及变量的命名等原因,它们之间没有任何共同点。
如果有人拿接下来的approach of this answer到另一个Q. ... "Segregate an array based on same name")...几天前,一个...
- 只需要更改如何合并两个要分组项目的属性的实现(第24行),并且
- 只需提供一个要分组在所有其他列表项周围的目标值的正确键名(第42行)即可。
...代码...
// reduce function that groups
// any data item generically by key.
function groupByKeyAndMergeProperties(collector,item) {
const { merge,key,index,list } = collector;
const groupKey = item[key];
let groupItem = index[groupKey];
if (!groupItem) {
// use `Object.assign` initially in order
// to not mutate the original (list's) reference.
groupItem = index[groupKey] = Object.assign({},item);
list.push(groupItem);
merge(groupItem,null);
} else {
merge(groupItem,item);
}
return collector;
}
// task specific merge function,// here,according to the OP's goal.
function mergeItemNames(targetItem,sourceItem) {
if (sourceItem !== null) {
targetItem.Name = `${ targetItem.Name } & ${ sourceItem.Name }`;
}
}
const sampleList = [
{ flatNum: 1,Name: "emma" },Name: "april" },Name: "june" },{ flatNum: 3,Name: "john" }
];
console.log(
sampleList.reduce(groupByKeyAndMergeProperties,{
// task specific reduce configuration.
merge: mergeItemNames,key: 'flatNum',index: {},list: []
}).list
);
.as-console-wrapper { min-height: 100%!important; top: 0; }