Map array with arrays into a array

Question

Lets say for example i have this array with arrays:

var arrayWithArrays = [["peter","director","40"],["marie","author","10"],["marie","author","6"],["peter","director","9"]];

I want a new array that will have this format (unique name, all the hours for the unique name added up):

var chartData = [["peter", 49],["marie",16]];

I have tried allot of things but nothing works as expected. Mapping doesnt work like expected

        var temp = _.map(arrayWithArrays ,function(x){

            if(chartData[x[0]]){
                chartData[x[0]] += parseInt(x[2]);
            }else{
                chartData[x[0]] = parseInt(x[2]);
            }
        });

Old fashioned way also doesnt deliver

        for (var x = 0; x < arrayWithArrays.length; x++) {
            if(chartData.length != 0){
                for (var i = 0; i < chartData.length; i++) {
                    if(chartData[i][0] == arrayWithArrays[x][0]){
                        chartData[i][2] += parseInt(arrayWithArrays[x][2]);
                    }else{
                        var array = [];
                        array[0] = arrayWithArrays[x][0];
                        array[1] = parseInt(arrayWithArrays[x][2]);
                        chartData.push(array);
                    }
                }
            }else{
                var array = [];
                array[0] = arrayWithArrays[x][0];
                array[1] = parseInt(arrayWithArrays[x][2]);
                chartData.push(array);
            }
        }

I think i am overthinking it and i make it more complex than it really is...someone has an idea to get me out of this headache ? I already spent 3 hours over this

Are you using underscore.js?

Teemu
– Teemu

2016-07-15 07:58:04 +00:00
Commented Jul 15, 2016 at 7:58 — Teemu
– Teemu, Commented Jul 15, 2016 at 7:58
What is chartData? Where is it defined?

hindmost
– hindmost

2016-07-15 07:59:09 +00:00
Commented Jul 15, 2016 at 7:59 — hindmost
– hindmost, Commented Jul 15, 2016 at 7:59
@Teemu yes i use underscore.

MichaelAngelo
– MichaelAngelo

2016-07-15 08:00:52 +00:00
Commented Jul 15, 2016 at 8:00 — MichaelAngelo
– MichaelAngelo, Commented Jul 15, 2016 at 8:00

Nina Scholz · Accepted Answer · 2016-07-15 11:01:59Z

3

You could use Array#forEach for it and use an object for the reference to the inserted array.

var arrayWithArrays = [["peter", "director", "40"], ["marie", "author", "10"], ["marie", "author", "6"], ["peter", "director", "9"]],
    result = [];

arrayWithArrays.forEach(function (a) {
    if (!this[a[0]]) {
        this[a[0]] = [a[0], 0];
        result.push(this[a[0]]);
    }
    this[a[0]][1] += +a[2];
}, Object.create(null));

console.log(result);

Edit for results in usersData and rolesData:

var arrayWithArrays = [["peter", "director", "40"], ["marie", "programmer", "10"], ["peter", "author", "10"], ["peter", "author", "6"], ["peter", "director", "9"], ["marie", "author", "2"], ["marie", "author", "3"], ["marie", "programmer", "9"]],
    usersData = [],
    rolesData = [];

arrayWithArrays.forEach(function (a) {
    if (!this.user[a[0]]) {
        this.user[a[0]] = { drilldown: a[0], name: a[0], y: 0, };
        usersData.push(this.user[a[0]]);
    }
    this.user[a[0]].y += +a[2];            
    if (!this.role[a[0]]) {
        this.role[a[0]] = { load: { id: a[0], data: [] } };
        rolesData.push(this.role[a[0]].load);
    }
    if (!this.role[a[0]][a[1]]) {
        this.role[a[0]][a[1]] = [a[1], 0];
        this.role[a[0]].load.data.push(this.role[a[0]][a[1]]);
    }
    this.role[a[0]][a[1]][1]+= +a[2];
}, { user: Object.create(null), role: Object.create(null) });

console.log(usersData);
console.log(rolesData);

edited Jul 15, 2016 at 11:01

answered Jul 15, 2016 at 7:57

Nina Scholz

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8 Comments

evolutionxbox Over a year ago

I love this... "How to map array to another array" ... "use map?"

Nina Scholz Over a year ago

sorry, it should be use forEach.

MichaelAngelo Over a year ago

@NinaScholz works perfectly! I am trying to figure out how to read your code so that i can create a second array that looks like this ["peter","peter",["director",2]]. (Counting how many times role occurs.) should i create another loop or can it be done in the same one again ?

Nina Scholz Over a year ago

i suggest to change the data structure to an object. there is a better access to the properties, and it's better readable. to the question: as result, you want some arrays, filled with the name of the same role, and at last, an array with role and count?

MichaelAngelo Over a year ago

example: var chartData = [["peter", 49,["director",2,"actor",4]],["marie",16],["roleName",count]]; it should take a unique role and count how many times it occured

|

RomanPerekhrest · Accepted Answer · 2016-07-15 08:08:59Z

0

The solution using Array.forEach and Object.keys functions:

var arrayWithArrays = [["peter","director","40"],["marie","author","10"],["marie","author","6"],["peter","director","9"]],
    names = {}, result;

arrayWithArrays.forEach(function (arr) {
    (names[arr[0]])? names[arr[0]][1] += +arr[2] : names[arr[0]] = [arr[0], +arr[2]];
});
result = Object.keys(names).map(function (n) {
    return names[n];
});

console.log(JSON.stringify(result, 0, 4));

answered Jul 15, 2016 at 8:08

RomanPerekhrest

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Comments

cstuncsik · Accepted Answer · 2016-07-15 09:09:20Z

0

Similar to other solutions here but with Array.prototype.reduce and Object.keys

var arrayWithArrays = [
  ["peter", "director", "40"],
  ["marie", "author", "10"],
  ["marie", "author", "6"],
  ["peter", "director", "9"]
];

var obj = arrayWithArrays.reduce(function(acc, item) {
  if (!acc[item[0]]) acc[item[0]] = 0;
  acc[item[0]] += +item[2];
  return acc;
}, {});

var newArr = Object.keys(obj).map(function(i) {
  return [i, obj[i]];
});

console.log(newArr);

edited Jul 15, 2016 at 9:09

answered Jul 15, 2016 at 8:49

cstuncsik

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