通过对象属性从对象数组中删除少于元素的元素

Question

I have an array of objects:

[
{
  incoming_number: 1,
  incoming_number_fraction: 0,
  article:'a1'
},
{
  incoming_number: 2,
  incoming_number_fraction: 0,
  article:'a2'
},
{
  incoming_number: 2,
  incoming_number_fraction: 2,
  article:'a3'
},
{
  incoming_number: 3,
  incoming_number_fraction: 0,
  article:'a4'
},
{
  incoming_number: 4,
  incoming_number_fraction: 0,
  article:'a5'
},
{
  incoming_number: 4,
  incoming_number_fraction: 2,
  article:'a6'
},
{
  incoming_number: 4,
  incoming_number_fraction: 4,
  article:'a7'
},
]

The task is removing elements from array by this logic: if there are elements with similar "incoming_number" , we must save the element with max "incoming_number_fraction" and remove all others.
The result should be:

[
{
      incoming_number: 1,
      incoming_number_fraction: 0
},
{
      incoming_number: 2,
      incoming_number_fraction: 2
},
{
      incoming_number: 3,
      incoming_number_fraction: 0
},
{
      incoming_number: 4,
      incoming_number_fraction: 4
},
]  

There are a lot of elements in array (more than 10000) and I want to do this operation in the minimum number of steps.

EDIT
I try something like this:

for (let i = 0; i < arr.length ; i++) {  
if (arr[i]['incoming_number'] === arr[i + 1]['incoming_number']) {
  let j = i + 1
  while (arr[j]['incoming_number'] === arr[j + 1]['incoming_number']) {
    j++
  }
}

arr.splice(i, j-1)
}  

But it doesn't work...
EDIT 2
Adding more information about objects in array.

Answer 1

Using findIndex or grep to find the selected number in a big array is bad for performance. so using the number as a property will be the fastest way to find the object and change incoming_number_fraction .

Using grep, findindex may result in a samller code but not better performance and in your case you need performance more then smaller code.

have a look at my example and let me know.

 var arr=[ { incoming_number: 1, incoming_number_fraction: 0, article:'a1' }, { incoming_number: 2, incoming_number_fraction: 0, article:'a2' }, { incoming_number: 2, incoming_number_fraction: 2, article:'a3' }, { incoming_number: 3, incoming_number_fraction: 0, article:'a4' }, { incoming_number: 4, incoming_number_fraction: 0, article:'a5' }, { incoming_number: 4, incoming_number_fraction: 2, article:'a6' }, { incoming_number: 4, incoming_number_fraction: 4, article:'a7' }, ] var finalResult = []; var result = {}; var includedNumbers = [] arr.forEach(function(item){ var number = item.incoming_number; if (!result[item.incoming_number]){ // with Index, is the fastest way result[number] = item; includedNumbers.push(number); }else { if (result[number].incoming_number_fraction< item.incoming_number_fraction ){ result[number] = item; } } }); // now lets clean the result includedNumbers.forEach(function(item){ finalResult.push(result[item]) }); console.log(finalResult) 

Answer 2

the easiest way to achieve this is using reduce , because with one iteration you will get your result and you apply your logic directly to the result array.

 const obj = [{ incoming_number: 1, incoming_number_fraction: 0 }, { incoming_number: 2, incoming_number_fraction: 0 }, { incoming_number: 2, incoming_number_fraction: 2 }, { incoming_number: 3, incoming_number_fraction: 0 }, { incoming_number: 4, incoming_number_fraction: 0 }, { incoming_number: 4, incoming_number_fraction: 2 }, { incoming_number: 4, incoming_number_fraction: 4 }, ] const result = obj.reduce((accum, currentValue) => { const index = accum.findIndex(item => currentValue.incoming_number === item.incoming_number); //if the index is -1 it means we didn't added that entry, so we just push it. if (index === -1) { accum.push(currentValue); } else { //this means that we have an entry with that incoming number, then we compare the incoming_number_fraction if (currentValue.incoming_number_fraction > accum[index].incoming_number_fraction) { accum[index] = currentValue; } } return accum; }, []) console.log(result)