如何将值从数组添加到对象？

Question

I've got an array :

let array = ["1#2","2#2","32#1","43#3","44#4","1#1","54#2","1#1"];

I've got a RegExp (/(\\d+)#(\\d+)/g) and could .exec() to the one of the group; On this RegExp I've got two groups of digits.

If ("key"/ first group) equal we sum value of this ("key" first group) .

How can I get this answer:

let answer = [
    { key: 1, value: 4 },     <==sum value of equal keys
    { key: 2, value: 2 },
    { key: 32, value: 1 },
    { key: 43, value: 3 },
    { key: 44, value: 4 },
    { key: 54, value: 2 } 
];

I'm trying to do this like :

let itemObject = {
    key: '',
    value: ''
}

array.map((item) => {
        let itemNumber = RegExp.exec(item);
        itemObject.key = itemNumber[1];
        itemObject.value = itemNumber[2];
        this.emptyArray.push(itemObject);
      })

But this not working ... and I don't know what to do.

Answer 1

You don't have to use regex here, you can use split method to get keys and values. Additionally you can use reduce to get the result:

  let array = ["1#2","2#2","32#1","43#3","44#4","1#1","54#2","1#1"]; let answer = array.reduce((arr, curr)=> { let [key, value] = curr.split('#'); let existing = arr.find(x => x.key === +key); if(existing){ existing.value += +value; } else { arr.push({key:+key, value: +value}); } return arr; }, []); console.log(answer); 

Answer 2

You could take a map and check if the key and value is equal. Then add the actual value.

 var array = ["1#2","2#2","32#1","43#3","44#4","1#1","54#2","1#1"], result = Array.from( array .reduce( (m, s) => (([k, v]) => m.set(k, (m.get(k) || 0) + v))(s.split('#').map(Number)), new Map ) .entries(), ([key, value]) => ({ key, value }) ); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

Answer 3

why don't you iterate over array, split on # and take the first value as key and second as its corresponding value and put them in a hash map. (if you are sure # is used as splitter always).

Answer 4

An alternative is splitting by # and using the function reduce to group the objects.

 let array = ["1#2","2#2","32#1","43#3","44#4","1#1","54#2","1#1"]; let result = Object.values(array.reduce((a, c) => { let [key, value] = c.split('#'), accumKey = key + '|' + value, currentValue = key === value ? value : 0; (a[accumKey] || (a[accumKey] = {key, value: 0})).value += Number(value); return a; }, {})); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; }