Why second loop don't work?

Tell us what’s happening:

Your code so far


function filteredArray(arr, elem) {
let newArr = [];
// Only change code below this line
   for (let i = 0; i < arr.length; i++) {
     //console.log(arr[i]);
    //  console.log(arr[i].indexOf(elem));
      for (let j = 0; j < arr[i]; j++) {
        // console.log(arr[i].indexOf(elem));
        //console.log(arr[j]);
          if(arr[i].indexOf(elem) === -1){
             return newArr.push(arr[i]);
          }else{
              return newArr;
          }
      }
   }
// Only change code above this line
return newArr;
} 

console.log(filteredArray([[3, 2, 3], [1, 6, 3], [3, 13, 26], [19, 3, 9]], 3));

I think you should change

for (let j = 0; j < arr[i]; j++) {

this line to this

for (let j = 0; j < arr[i].length; j++) {

i didn’t understand , why i should get length about index arr[i]?

in first loop you used arr.length so in second loop arr[i] lets assume i = 0 arr[i] becomes

[3, 2, 3]

so you’re comparing j with a list in the second loop instead of that you change arr[i] to arr[i].length will be equal to 3 so second loop iterate 3 times and in the second loop you should change arr[i] to arr[i][j]
arr[i] is array so yoru code will be

      for (let j = 0; j < arr[i].length; j++) {
        // console.log(arr[i][j].indexOf(elem));
        //console.log(arr[i][j]);
          if(arr[i][j].indexOf(elem) === -1){
             return newArr.push(arr[i][j]);
          }else{
              return newArr;
          }
      }

This will not work: j < arr[i], j is a number, arr[i] an array, the comparison doesn’t do what you want. You will need to use j < arr[i].length (in the same way that in the outer array you do i < arr.length)


Also,

remember that a return statement will stop the function and return something.
Remember also that push() returns the new length of the array


I suggest you look at your code with this tool: http://pythontutor.com/javascript.html

i catch the answer. i don’t need the second loop because i don’t need index array, i’m just want to check if number is not in array push array, without return , because I don’t need return anything to console, also your website is gooooooood