Inventory Update - how to create a 2D array

JavaScript
1

I am getting the correct values returned but they are formatted as string instead of an array of arrays. How do I use arr.push() to get a 2D array?

My code so far:

function updateInventory(arr1, arr2) {
    //pseudocode:
    //Get all 2nd element values of first array
    //Check each of those against each of the 2nd element values of 2nd array
      //If there is NO match, add that element's 1st and 2nd value (from 2nd array) to 1st array
      //If there is a match, add to that element's 1st value (in 1st array)

    let newArr = [];
    let remArr = [];

    //Comparing each name in arr1 against all names in arr2. If match, we want to add to total.
    for(var i = 0; i < arr1.length; i++){
      for(var k = 0; k < arr2.length; k++){
        if(arr2[k].indexOf(arr1[i][1]) > -1){
          let newTotal = arr1[i][0] + arr2[k][0];
          newArr.push(newTotal,arr1[i][1])
        }
      }
    }

    let onlyNamesArr2 = [];
    for(var n = 0; n < arr2.length; n++){
       onlyNamesArr2.push(arr2[n][1]);
     }
    for(var m = 0; m < arr1.length; m++){
      if(onlyNamesArr2.indexOf(arr1[m][1]) === -1){
        remArr.push(arr1[m]);
      }
    }


    let onlyNamesArr1 = [];
    for(var a = 0; a < arr1.length; a++){
      onlyNamesArr1.push(arr1[a][1]);
    }

    for(var j = 0; j < arr2.length; j++){
      if(onlyNamesArr1.indexOf(arr2[j][1]) > -1){
        //do nothing
      }else {
        newArr.push([arr2[j]])
      };
    }

    let finalArr = newArr + remArr;


}

// Example inventory lists
var curInv = [
    [21, "Bowling Ball"],
    [2, "Dirty Sock"],
    [1, "Hair Pin"],
    [5, "Microphone"]
];

var newInv = [
    [2, "Hair Pin"],
    [3, "Half-Eaten Apple"],
    [67, "Bowling Ball"],
    [7, "Toothpaste"]
];
//
updateInventory(curInv, newInv);

Link to the challenge:
https://learn.freecodecamp.org/coding-interview-prep/algorithms/inventory-update/

2

And by the way, you finalArr is wrong answer so it won’t be accepted anyway. Try to come up a new solution, ok :slight_smile:

3

Thanks @dangtu. Do you mean it’s not in alphabetical order…? Or something else is wrong…?

4

Everything. Do you know how to debug you program? It’s easy. Wrap any suspicious functions, objects, etc into console.log. The browser will give the value that object/function returns in console.

Here, take a look at this:

image
image1257×459 39.6 KB

  • Red line is a debug line.
  • Pink draw is comparison between correct answer and yours.
5

I think you might be looking in the wrong spot. See this a little lower down:

Capture
Capture1053×330 51.8 KB

6

Ha ha, indeed, the bug supposes to lie in the Toothpaste (Your result return Toothpaste2)

7

See console.log of finalArr:

Capture
Capture864×82 10.1 KB

If you read from left to right as [number, item], [number, item] etc you can see that toothpaste is 7.

I think my real problem is what I posted in the first place, i.e. finalArr is not posting as a 2D array.

That is the problem I need to solve.

8

I think you should stop using this + operator for array. It doesn’t have a function as join in array. If you wanna join 2 arrays, let use newArr.concat(remArr). You could return it immediately return newArr.concat(remArr)

9

Haha - we’re getting closer! :slight_smile:

Capture
Capture984×338 24.1 KB

I think now I have to go back into the creation of newArr and remArr to see how those are being created.

10

And getting a little closer still…

Capture
Capture1251×121 19.9 KB

Next step: must alphabetize then split up the final array into a 2D array of pairs.

11

You have to create 2Darr somewhere in here before thinking about sort it out.
image