比较 2 个在 Javascript 中不起作用的数组的值

Question

im trying to compare between two arrays, whether they have same value at same place, same values at different places or not the same at all. after comparing I want to enter a char to a third array to indicate the result. my code doesnt work for some reason... its not comparing correctly. what am i doing wrong?

var numInput = [1,2,3,4];
var numArr = [2,5,3,6];
var isBp;
var i,j;
  for ( i = 0; i < 4; i++)
   {
     if (numInput[i] == numArr[i])
     {  isBP[i] = "X"; }
     else
     {
       for ( j = 0; j<4; j++)
       {
         if (numInput[i] == numArr[j])
          {isBP[i] = "O";}
         else
          { isBP[i] = "-"; }
       }

     }

     }

the result should be:

isBP = [O,-,X,-]

Answer 1

This is a fairly simple array map operation. If I understand correctly you want an X when they match and an O when they don't and that doesn't exist at all and - when it exists but at different location

 var numInput = [1,2,3,4]; var numArr = [2,5,6,4]; var isBP = numInput.map((n,i) => ((n === numArr[i] ? 'X' : numArr.includes(n) ? '-': 'O'))) console.log(isBP)

Answer 2

It looks like you'd like to output:

• X if the numbers at the same indexes are equal
• • if they are not equal at the same indexes, but the number is found elsewhere
• O if the number from the first array doesn't exist in the second at all

if so:

var a1 = [1, 2, 3];
var a2 = [1, 3, 4];

var result = a1.map((n, i) => {
  var match = a2.indexOf(n);
  if (match === i) {
    return "X"
  } else if (match > -1) {
    return "O";
  } else {
    return "-";
  }
});

console.log(result); // prints [ 'X', '-', 'O' ]