So I want to create a function in js which takes two arrays and pare them and give a score depending on how many spots in the two arrays match. Is it right or it's bd written. I am new on coding.

Another problem I have is when I try to execute it on chrome's console. It says that pare is not defined

let score = 0;
function pare(arr1, arr2) {
  for (let i = 0; i < arr2.length; i++) {
     for (let j = 0; j < arr1.length; j++) {
        if(arr1[j] === arr2[i]){
            score++;
        }   
    }
}

So I want to create a function in js which takes two arrays and pare them and give a score depending on how many spots in the two arrays match. Is it right or it's bd written. I am new on coding.

Another problem I have is when I try to execute it on chrome's console. It says that pare is not defined

let score = 0;
function pare(arr1, arr2) {
  for (let i = 0; i < arr2.length; i++) {
     for (let j = 0; j < arr1.length; j++) {
        if(arr1[j] === arr2[i]){
            score++;
        }   
    }
}

• javascript
• arrays
• pare

• Should multiple matches of one sport be counted as well. The score of [1,2] and [1,1,1,1,2,2,2,2] should be 8? – Ori Drori Commented Apr 15, 2018 at 12:34
• I know I'm late to the party on this one, but the reason the function was defined was because you didn't have a closing bracket for the first for loop. ;-) – Jester Commented Jul 20, 2020 at 23:35

2 Answers 2

You can use .reduce() to find count of matched elements:

let arr1 = [1, 2, 3, 4, 5],
    arr2 = [3, 4, 5, 6, 7],
    pare = (a1, a2) => arr1.reduce((a, c) => a + arr2.includes(c), 0);

console.log(pare(arr1, arr2));

Alternatively, you can use .filter() to find array of matched elements and use its length to determine the count.

let arr1 = [1, 2, 3, 4, 5],
    arr2 = [3, 4, 5, 6, 7],
    pare = (a1, a2) => arr1.filter(v => arr2.includes(v)).length;

console.log(pare(arr1, arr2));

Docs:

• Array.prototype.reduce()
• Array.prototype.includes()
• Array.prototype.filter()
• Arrow Functions

This should work for you:

Updated the code as required by you :

let arr1 = [1, 2, 3, 4];
let arr2 = [3,2,3,4,5];
function pare(arr1,arr2){
  let count=0;
  const max=arr1.length>arr2.length ? arr2.length : arr1.length;
  for(var i=0;i<max;i++){
    if(arr1[i]==arr2[i]){
      count++;
    }
  }
  return count;
}
console.log(pare(arr1,arr2));