如何停止复制键值

Question

I have an array serialNumbers. It can look like this.

lot: 1  Serial: 2
lot: 1  Serial: 3
lot: 1  Serial: 4

... and so on. or it may look like

lot: 1  Serial: 5
lot: 1  Serial: 9
lot: 8  Serial: 2
lot: 8  Serial: 4

var dictSerials = []
if (serialNumbers.length > 0) 
    for (var i of serialNumbers) {
        dictSerials.push({
            key: i.value.lot,
            value: i.value.serial
        })
    }

This is what I was trying to use to get things working but this creates a key and value for each one listed. I want my outcome to be an object like:

Key: 1  Value: 2, 3, 4, 5, 9
Key: 8  Value: 2, 4

Can anyone help me figure this out? Thank you!

Answer 1

Not sure if there is a better/easier way, but this would do it:-

 var array = [{
      name: "foo1",
      value: "val1"
    }, {
      name: "foo1",
      value: ["val2", "val3"]
    }, {
      name: "foo2",
      value: "val4"
    }];

    var output = [];

    array.forEach(function(value) {
      var existing = output.filter(function(v, i) {
        return v.name == value.name;
      });
      if (existing.length) {
        var existingIndex = output.indexOf(existing[0]);
        output[existingIndex].value = output[existingIndex].value.concat(value.value);
      } else {
        if (typeof value.value == 'string')
          value.value = [value.value];
        output.push(value);
      }
    });

    console.dir(output);

Answer 2

An alternative to accomplish your requirement, is using the function reduce to group the keys and values.

 let array = [{lot: 1, Serial: 2},{lot: 1, Serial: 3},{lot: 1, Serial: 4},{lot: 1, Serial: 5},{lot: 1,Serial: 9},{lot: 8,Serial: 2},{lot: 8,Serial: 4}], result = Object.values(array.reduce((a, c) => { (a[c.lot] || (a[c.lot] = {Key: c.lot, Value: []})).Value.push(c.Serial); return a; }, {})); console.log(result); 

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Answer 3

function getDictSerials(serialNumbers) {

    var dictSerials = {};

    if (serialNumbers.length > 0) {
        for (let i of serialNumbers) {
            let lot = i.lot;
            let serial = i.serial;

            if (!dictSerials[lot]) { // If the key isn't found - intiate an array
                dictSerials[lot] = [];
            }

            dictSerials[lot].push(serial) // push the serial to the corresponding lot
        }
    }

    return dictSerials;
}

let serialNumbers = [
    {lot : 1, serial : 2},
    {lot : 1, serial : 3},
    {lot : 1, serial : 4},
    {lot : 1, serial : 5},
    {lot : 1, serial : 9},
    {lot : 8, serial : 2},
    {lot : 8, serial : 4}
];

let desiredObj =  {
    dictSerials: getDictSerials(serialNumbers)
}

JSON.stringify(desiredObj); // {"dictSerials":{"1":[2,3,4,5,9],"8":[2,4]}}

Answer 4

var dictSerials = []
if (serialNumbers.length > 0) {
    for (var i of serialNumbers) {

      if(!dictSerials[i.value.lot]){
          dictSerials[i.value.lot] = [];
      }

       dictSerials[i.value.lot][] = i.value.serial;
    }
}

The code above will add values to their corresponding keys.

Answer 5

here's a simple approach using two forEach loops :

 const arr = [ {lot : 1, Serial : 2}, {lot : 1, Serial : 3}, {lot : 1, Serial : 4}, {lot : 1, Serial : 5}, {lot : 1, Serial : 9}, {lot : 8, Serial : 2}, {lot : 8, Serial : 4} ] let grouped = [], result = []; arr.forEach((e) => { (result[e.lot] || (result[e.lot] = [])).push(e.Serial) }) result.forEach((e, i) => { grouped.push({ "key": i, "value": e.join(',') }) }); console.log(grouped) 

Answer 6

You can use a Map for this.

 var serialNumbers = [ {value:{lot:1, serial: 2}}, {value:{lot:1, serial: 3}}, {value:{lot:1, serial: 4}}, {value:{lot:1, serial: 5}}, {value:{lot:1, serial: 9}}, {value:{lot:8, serial: 2}}, {value:{lot:8, serial: 4}}, ]; var dictSerials = new Map(); if (serialNumbers.length > 0) { for (var i of serialNumbers) { if(!dictSerials.has(i.value.lot)) { dictSerials.set(i.value.lot, [i.value.serial]); } else { var v = dictSerials.get(i.value.lot); v.push(i.value.serial); dictSerials.set(i.value.lot, v); } } } //Output for (var [key, value] of dictSerials.entries()) { console.log("Key: " + key + " Value: " + value.join(",")); }