Perform Lookup On Two Arrays And Add Element From Second Array To First Array

I have two arrays that I have looped over to match an element from the 1st array vals1 in the second onevals2. If the element(index [i][0]) from vals1 is present in vals2(index [j]

Solution 1:

• Iterate through all items in the first 2D array (vals1). You can do that with forEach, for example.
• For each item in vals1, you want to look for the same item in vals2. You can use find for that. Since items are the first element in each inner array, you would have to check whether item1[0] === item2[0].
• If the item is found, push the corresponding value item2[1] to the item's inner array in vals1.
• If the item is not found (find returns undefined), push the string "Unassigned" instead.

Code snippet:

functionlookup(vals1, vals2) {
  vals1.forEach(item1 => {
    const item2 = vals2.find(item2 => item1[0] === item2[0]);
    const newValue = item2 ? item2[1] : "Unassigned";
    item1.push(newValue);
  });
  return vals1;
}

Regular function syntax:

functionlookup(vals1, vals2) {
  vals1.forEach(function(item1) {
    const item2 = vals2.find(function(item2) {
      return item1[0] === item2[0]
    });
    const newValue = item2 ? item2[1] : "Unassigned";
    item1.push(newValue);
  });
  return vals1;
}

Solution 2:

Try this:

functionmyFunc() {
  let v1 = [[ 'item3', 3, 2, 6 ],[ 'item6', 4, 7, 28 ],[ 'item8', 1, 8, 8 ],[ 'item2', 6, 12, 72 ]];
  let v2 = [[ 'item1', 15 ],[ 'item2', 4 ],[ 'item3', 1 ],[ 'item4', 2 ]]; 
  let v0 =v2.map(r=>{return r[0]});//just getting all of the the first elements of v2 in a flatten array for  use with indexOf
  v1.forEach((r,i)=>{
    let idx=v0.indexOf(r[0]); 
    if(idx>-1) {//if idx is greater than -1 the matches first element v2
      v1[i].push(v2[idx][1]);
    }else{
      v1[i].push('UnAssigned')
    }
  });
  console.log(v1);
}

The output was:

[ [ 'item3', 3, 2, 6, 1 ],
  [ 'item6', 4, 7, 28, 'UnAssigned' ],
  [ 'item8', 1, 8, 8, 'UnAssigned' ],
  [ 'item2', 6, 12, 72, 4 ] ]