Sum the second parameter of an array

Question

I have an object, which I need to add up to a number of times words appear. Ex:

{
step1: ["luiz"]
step2: ["pedro"]
step3: ["luiz"]
step4: ["luiz"]
step5: ["luiz"]
}

I tried using .map, .forEach, .filter, but they all come back undefined.

.filter

let irmas = answers.filter((answer) => answer[1] === 'luiz)

.map

let contagemRespostas = answers.map(function(answer, index) {
      return contagemRespostas.index
    })

How do I get names only and add values?

EDIT:

The return is something like:

{ 'luiz': 3, 'pedro': 2 } or the highest value { 'luiz': 3 }

`I tried using .map, .forEach, .filter, but they all come back undefined.` - Please share any/all of these attempts. Sounds like you might just be forgetting to `return` within the predicate. Your question could also use with a bit of clarification. What is your desired result? — Tyler Roper, Dec 11 '19 at 18:49
something like this might help you get started: https://stackoverflow.com/a/56929965/2280670 drop that sort of code and loop over the object keys — Rohan Bhangui, Dec 11 '19 at 18:52
still use some form of the code i commented above and then combine the resulting objects — Rohan Bhangui, Dec 11 '19 at 19:09
I tried to use, but o got nothing on console.log. `var count = respostas.reduce((a,c)=> (a[c]=++a[c]||1,a) ,{}); console.log(count)` — Luiz Henrique, Dec 11 '19 at 19:12

score 2 · Accepted Answer · answered Dec 11 '19 at 20:26

2

You could use a reduce to create an object with the values

const data = {
  step1: ["luiz"],
  step2: ["pedro"],
  step3: ["luiz"],
  step4: ["luiz"],
  step5: ["luiz"],
}
    
const result = Object.values(data).flat().reduce((acc, cur) => {
  acc.hasOwnProperty(cur) ? acc[cur]++ : acc[cur] = 1
  return acc
}, {})

console.log(result) // {luiz: 4, pedro: 1}

answered Dec 11 '19 at 20:26

Prince Vasconcelos

46
2

This works, thanks! How i can get only the numbers out of the reduce? – Luiz Henrique Dec 12 '19 at 15:40

score 1 · Answer 2 · answered Dec 11 '19 at 19:19

Try something like this:

https://jsfiddle.net/bwmfhqev/2/

var foo = {
    step1: ["luiz"],
    step2: ["pedro"],
    step3: ["luiz"],
    step4: ["luiz"],
    step5: ["luiz"]
}

let result = {};

console.log(Object.keys(foo));

// loop over the keys of the object
for(var key of Object.keys(foo)) {
    // get the number of occurrences of words in the array for each key
    let count= foo[key].reduce((a,c)=> (a[c]=++a[c]||1,a) ,{});
  //combine everything into 1 object
  for(var key2 of Object.keys(count)) {
    console.log(count[key2]);
    if(key2 in result) {
        result[key2] = result[key2] + count[key2];
    }
    else {
        result[key2] = count[key2];
    }
  }
}

console.log(result);

The idea here to process each key in the original object. and then create an object out of each one that gets the number of occurrences of each word for each key. Then combine them all into 1 object

Sum the second parameter of an array

2 Answers2