Analyzing objects within an array for similarities

Question

Analyzing objects within an array for similarities

Suppose I have an array containing objects:

 var arr = [ 
   { id: 1, pt: 0 },
   { id: 2, pt: 12 },
   { id: 3, pt: 7 },
   { id: 4, pt: 45 },
   { id: 5, pt: 123 },
 ];

I am looking to loop through this array (possibly using array.forEach or array.map) and compare the pt attribute of each item with that of the other items in the array. My goal is to identify the three other items with values closest to the current item's pt value. For instance, for id: 1, the closest items in value would be 2, 3, and 4. Similarly, for id: 3, it would be 1, 2, and 4, and so on. How can I achieve this?

javascript arrays object compare

Answer 1

Answer №1

In order to obtain the desired outcome, one could apply a filtering mechanism to remove the pivot element and then arrange the data based on absolute difference, ultimately selecting the specified number of items as output.

function closest(n, { id, pt }) {
    return array
        .filter(o => o.id !== id)
        .sort((a, b) => Math.abs(a.pt - pt) - Math.abs(b.pt - pt))
        .slice(0, n);
}

var array = [{ id: 1, pt: 0 }, { id: 2, pt: 12 }, { id: 3, pt: 7 }, { id: 4, pt: 45 }, { id: 5, pt: 123 }],
    result = array.map(o => Object.assign({}, o, { closest: closest(3, o) }));

console.log(result);

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

Answer 2

In order to obtain the desired outcome, one could apply a filtering mechanism to remove the pivot element and then arrange the data based on absolute difference, ultimately selecting the specified number of items as output.

function closest(n, { id, pt }) {
    return array
        .filter(o => o.id !== id)
        .sort((a, b) => Math.abs(a.pt - pt) - Math.abs(b.pt - pt))
        .slice(0, n);
}

var array = [{ id: 1, pt: 0 }, { id: 2, pt: 12 }, { id: 3, pt: 7 }, { id: 4, pt: 45 }, { id: 5, pt: 123 }],
    result = array.map(o => Object.assign({}, o, { closest: closest(3, o) }));

console.log(result);

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

Answer 3

Answer №2

Let's start by organizing the array:

array.sort((a, b) => a.pt - b.pt);

Next, the nearest elements can be found directly before or after the element. To locate them, simply move forward and backward:

function findNearest(position, count) {
  let lower = position - 1, upper = position + 1;
  const calculateDistance = index => Math.abs(array[position].pt - array[index].pt);
  const result = [];
  while(result.length < count) {
    if(lower >= 0 && calculateDistance(lower) < calculateDistance(upper)) {
       result.push(array[lower--]);
    } else if(upper < array.length) {
       result.push(array[upper++]);
    } else break;
  }
 return result;
}

To find the five closest ancestors of the first element:

findNearest(0, 5)

Answer 4

Let's start by organizing the array:

array.sort((a, b) => a.pt - b.pt);

Next, the nearest elements can be found directly before or after the element. To locate them, simply move forward and backward:

function findNearest(position, count) {
  let lower = position - 1, upper = position + 1;
  const calculateDistance = index => Math.abs(array[position].pt - array[index].pt);
  const result = [];
  while(result.length < count) {
    if(lower >= 0 && calculateDistance(lower) < calculateDistance(upper)) {
       result.push(array[lower--]);
    } else if(upper < array.length) {
       result.push(array[upper++]);
    } else break;
  }
 return result;
}

To find the five closest ancestors of the first element:

findNearest(0, 5)

Analyzing objects within an array for similarities

Answer №1

Answer №2

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