Iterating through objects in an array using JavaScript should only happen after the current object

Question

Iterating through objects in an array using JavaScript should only happen after the current object

As an illustration:

Starting from

[x0,x1,x2,x3] - x0 compares itself to x1,x2 and x3. 
x1 compares itself to x0, x2 and x3. And so forth...

To

[x0,x1,x2,x3] - x0 compares itself to x1,x2 and x3. 
x1 compares itself to x2 and x3 only. 
x2 only compares itself to x3. 
x3 doesn't have to make any comparisons at all.

My aim is to travel through an array in one specific direction, disregarding all elements before the current one.

for (var i = 0; i < boids.length; i++) { 
//boids is an array that includes elements "boid"


     var d = distSquared(this.position.x, this.position.y, boids[i].position.x, boids[i].position.y); 
       //calculate distance between current boid and all other boids in the array. 
       //Wanting to modify this to determine distance between current boid and all other boids ahead of this element in the array.

     if (boids[i] == this) { //if the boid being compared is itself, skip it.
            continue;
        }
}

How can I establish such a system?

javascript arrays

Answer 1

Answer №1

If you're in need of a solution, consider the following code snippet:

let array = [5,10,15,20];

for(let i=0; i<array.length; i++){
  for(let j=i+1; j<array.length; j++){
    console.log(i,j)
  }
}

Answer 2

If you're in need of a solution, consider the following code snippet:

let array = [5,10,15,20];

for(let i=0; i<array.length; i++){
  for(let j=i+1; j<array.length; j++){
    console.log(i,j)
  }
}

Answer 3

Answer №2

To exclude an element or elements from an array, you can utilize the Array.prototype.filter() method.

var arr = [1,2,3,4,5];
for (var i = 0; i < arr.length; i++) {
  var curr = arr[i];
  var not = arr.filter(function(_, index) {
    return index != i
  });
  console.log(`curr:${curr}`);
  not.forEach(function(el) {
    console.log(`${curr} is not ${el}`)
  })
}

Answer 4

To exclude an element or elements from an array, you can utilize the Array.prototype.filter() method.

var arr = [1,2,3,4,5];
for (var i = 0; i < arr.length; i++) {
  var curr = arr[i];
  var not = arr.filter(function(_, index) {
    return index != i
  });
  console.log(`curr:${curr}`);
  not.forEach(function(el) {
    console.log(`${curr} is not ${el}`)
  })
}

Answer 5

Answer №3

One possible approach is outlined below. Ultimately, the method of comparison is left to your discretion.

const array = [5,10,15,20,25],
 outcome = array.map((element,index,array) => array.slice(index+1).map(number => element-number));
console.log(outcome);

Answer 6

One possible approach is outlined below. Ultimately, the method of comparison is left to your discretion.

const array = [5,10,15,20,25],
 outcome = array.map((element,index,array) => array.slice(index+1).map(number => element-number));
console.log(outcome);

Answer 7

Answer №4

I successfully tackled my problem by utilizing the Array.prototype.indexOf() method.

var j = boids.indexOf(this);
//obtain the index of the current element in the array.

if (j < boids.length) {
    // if the index is less than the total length of the array (e.g. moving through the array to elements ahead of the current element, disregarding those behind)

    //Perform calculations here

   j++; //increment j

}

Answer 8

I successfully tackled my problem by utilizing the Array.prototype.indexOf() method.

var j = boids.indexOf(this);
//obtain the index of the current element in the array.

if (j < boids.length) {
    // if the index is less than the total length of the array (e.g. moving through the array to elements ahead of the current element, disregarding those behind)

    //Perform calculations here

   j++; //increment j

}

Iterating through objects in an array using JavaScript should only happen after the current object

Answer №1

Answer №2

Answer №3

Answer №4

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