CODEWITHSUNDEEP
javascriptdictionaryfor-loop
Danilo Santos
Danilo Santos

Reputation: 3

How do I append dictionaries on an list?

I am trying to make a for loop that stores values in a dictionary and each iteration appends this dictionary to a list.

Already tried to attach using push() and index list, but no sucess.

json = {
    "MUNICIPIOS":[
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [10, 100, 1000]},
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [20, 200, 2000]},
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [30, 300, 3000]},
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [40, 400, 4000]}
    ]
};

var atributos = json["MUNICIPIOS"][0]["ATRIBUTOS"];
var municipios = json["MUNICIPIOS"];
var dimensoes = [];
var dicionario = {label:"", values:[]};


for (var atr = 0; atr < atributos.length; atr++){

    dicionario.label = atributos[atr];

    valores = [];
    for (var mun=0; mun < municipios.length; mun++){
        valores.push(municipios[mun]["VALORES"][atr]);
        dicionario.values = valores;
    }

    //dimensoes.push(dicionario);
    dimensoes[atr] = dicionario;
}

console.log(dimensoes);

The result is not as I wish:

// Actual result
[
  { label: 'atrib3', values: [ 1000, 2000, 3000, 4000 ] },
  { label: 'atrib3', values: [ 1000, 2000, 3000, 4000 ] },
  { label: 'atrib3', values: [ 1000, 2000, 3000, 4000 ] }
]

I need this:

// Expected result
[
  { label: 'atrib1', values: [ 10, 20, 30, 40 ] },
  { label: 'atrib2', values: [ 100, 200, 300, 400 ] },
  { label: 'atrib3', values: [ 1000, 2000, 3000, 4000 ] }
]

What am I doing wrong?

Upvotes: 0

Views: 48

Answers (1)

Jaromanda X
Jaromanda X

Reputation: 1

The issue with your code is where you "populate" dicionario - this one object is used and modified for all outputs dimensoes[atr]

var dicionario = {label:"", values:[]};

for (var atr = 0; atr < atributos.length; atr++){

    dicionario.label = atributos[atr];
    // snip - rest of your code
    dimensoes[atr] = dicionario;
}

One solution is to change the code so that each iteration has a new dicionario object to work with

var dicionario = {label:"", values:[]};

for (var atr = 0; atr < atributos.length; atr++){

    dicionario = {label:atributos[atr], values:[]};

    //dicionario.label = atributos[atr]; not required as it is set above
    // snip - rest of your code

    dimensoes[atr] = dicionario;
}

However, for a neat and tidy ES6+ solution:

const json = {
    "MUNICIPIOS":[
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [10, 100, 1000]},
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [20, 200, 2000]},
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [30, 300, 3000]},
        {"ATRIBUTOS":["atrib1","atrib2","atrib3"],"VALORES": [40, 400, 4000]}
    ]
};

const atributos = json.MUNICIPIOS[0].ATRIBUTOS;
const municipios = json.MUNICIPIOS;
const dimensoes = atributos.map((label, atr) => ({
  label,
  values: municipios.map(municipio => municipio.VALORES[atr])
}));
console.log(JSON.stringify(dimensoes, null, 4));

Upvotes: 2

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