How can I sum numbers which are substrings in variables?

Question

I was wondering how can you combine two variables (or more) that have the same string values, but different numbers.

For example, if you're combining a list of ingredients that are present in two different recipes. For a shopping list, like:

let ingredient1 = 1 + " apple";
let ingredient2 = 2 + " apple";
//combining ingredient1 and ingredient 2 would produce something like totalIngredients = 3 apples;

I can kind of figure out the pluralization, but I can't figure out how I can combine those two strings and for it to only increase the number if they're matching.

Answer 1

Make a json if I were you or an obj, something like this

const r = {
    {
        Item: “Apple”,
        Amount: 1 
    },
    {
        Item: “Apple”,
        Amount: 1 
    }
}

Then fetch the amount and put them together, along with ingredients matching

Answer 2

You can't combine both ingredients and it should make a calculation because let ingredient1 = 1 + " apple"; produces a string 1 apple

You can do something like this:

let ingredient = 'apple'
let ingredient1 = 1
let ingredient2 = 2
let totalIngredients = ingredient1 + ingredient2 + ingredient

Or maybe use a for loop to loop through all ingredients and add it to the total and then add 'apple'

Answer 3

Like others have noted, you should store your ingredients as objects. One way to achieve this is to have a class which stores the count and ingredient type. You can then define a function that checks for a given type and returns the count of ingredients.

 class Ingredient { constructor(count, type) { this.count = count; this.type = type; } }; const countByType = (type) => ingredients.reduce((sum, ingredient) => { if (ingredient.type === type) { return sum += ingredient.count; } return sum; }, 0); const ingredients = []; ingredients.push(new Ingredient(1, "apple")); ingredients.push(new Ingredient(2, "apple")); ingredients.push(new Ingredient(5, "orange")); console.log(`${countByType("apple")} apples`); console.log(`${countByType("orange")} oranges`);

Answer 4

How can I sum numbers which are substrings in variables?

By converting the substrings to numbers. If the numbers are at the start of the string you can just use parseInt .

parseInt(ingredient1) + parseInt(ingredient2)

To check the types, you could use for example

 let ingredient1 = 1 + " apple"; let ingredient2 = 2 + " apple"; let type1 = ingredient1.slice(ingredient1.indexOf(' ') + 1); let type2 = ingredient2.slice(ingredient2.indexOf(' ') + 1); if (type1 === type2) { console.log(`${parseInt(ingredient1) + parseInt(ingredient2)} ${type1}`); }