CODEWITHSUNDEEP
javascript
Rhyez
Rhyez

Reputation: 49

Iterating though a list issues

I am trying to take a list grocery list and checks it against things you already have and puts it in a new list. I am learning how to iterate though lists and cannot figure out why I am getting the output that I am. I want the output to be a list of things that where not found in the list of things you already have. The output at the moment prints out what I need but multiple times. Not sure why. Thanks

let groceryList = ['Bread', 'Cereal', 'Bagels', 'Water', 'Apple'];
let currentGrocery = ['Eggs', 'Lettuce', 'Milk', 'Cheese','Bread','Water','Oil'];
let newList = [];

for (let i = 0; i < groceryList.length; i++) {
    for (let j = 0; j < currentGrocery.length; j++){
        if (groceryList[i] !== currentGrocery[j]){
            newList.push(groceryList[i]);
        }
    }
}

console.log(newList);

Upvotes: 1

Views: 63

Answers (3)

Nina Scholz
Nina Scholz

Reputation: 386624

You oculd filter the array.

const
    groceryList = ['Bread', 'Cereal', 'Bagels', 'Water', 'Apple'],
    currentGrocery = ['Eggs', 'Lettuce', 'Milk', 'Cheese', 'Bread', 'Water', 'Oil'],
    newList = currentGrocery.filter(item => !groceryList.includes(item));

console.log(...newList);

Upvotes: 1

sourcloud
sourcloud

Reputation: 124

You push the item from your grocery list for every non-matching current grocery. What you want to do is to only push to the new list if there are no current grocery matches.

In a naive way, this could be achieved via

let found = false;
for (let i = 0; i < groceryList.length; i++) {
    for (let j = 0; j < currentGrocery.length; j++){
        if (groceryList[i] == currentGrocery[j]){
            found = true;
            break;
        }
    }
    if (found) {
        newList.push(groceryList[i]);
        found = false;
    }
}

A more readable approach makes use of the filter() and includes() functions:

let newlist = groceryList.filter(item => !currentGrocery.includes(item));
console.log(newlist);

Upvotes: 0

Crosper
Crosper

Reputation: 11

let groceryList = ['Bread', 'Cereal', 'Bagels', 'Water', 'Apple'];
let currentGrocery = ['Eggs', 'Lettuce', 'Milk', 'Cheese','Bread','Water','Oil'];
let newList = [];

currentGrocery.forEach(item =>{
     if (!groceryList.includes(item)) newList.push(item);
})

console.log(newList);

Upvotes: 1

Related Questions