Compare values of an array with values of an object

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1

I am making a simple code to practice some methods in JS, I would like to get a string transforms them into an array, convert the elements into number, and compare with the objects of my object, I will leave a snippet of code 

 const alf = {a : 1,b : 2,c : 3,d : 4,e : 5,f : 6,g : 7,h : 8,i : 9,j : 10,k : 11,l : 12,m : 13,n : 14,o : 15,p : 16,q : 17,r : 18,s : 19,t : 20,w : 21,u : 22,v : 23,x : 24,y : 25,z : 26}

const Calcular = () => {
  elemResult = document.getElementById("resultado");
  str = document.getElementById("texto").value;
  str = str.toLowerCase().split("").map(p => {
    if(p in alf){
      return alf[p];
    }
  }).sort((a, b) => a-b).map(n => );
  elemResult.innerText = str;
}

Within the last map, I would like to convert the numbers back into string

    
asked by anonymous 13.01.2018 / 01:23

2 answers

1

You can transform the array into a string using .join as in the example below (the parameter is the string used to separate the elements in the string, the default value is ',' ) 

const alf = { a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10, k: 11, l: 12, m: 13, n: 14, o: 15, p: 16, q: 17, r: 18, s: 19, t: 20, w: 21, u: 22, v: 23, x: 24, y: 25, z: 26 }

const Calcular = () => {
  elemResult = document.getElementById("resultado");
  str = document.getElementById("texto").value;
  str = str.toLowerCase().split("").map(p => {
    if (p in alf) {
      return alf[p];
    }
  }).sort((a, b) => a - b).join('');
  elemResult.innerText = str;
}

document.getElementById("texto").onblur = Calcular
<input type="text" id="texto" />
<div id="resultado"></div>
    
13.01.2018 / 01:47
0

Assuming that your converts the numbers back into String refers to converting them back into the original letters based on the number, you can use the find . First we build a function to get the key based on the value: 

const obterChave = (valor) => Object.keys(alf).find(key => alf[key] === valor);

I used Arrow Functions also since I was using it, which makes the code more consistent.

Then you just need to fill in the% w_that you left open by calling this function: 

.sort((a, b) => a-b).map(n => obterChave(n));

See an example of this working code: 

const alf = {a : 1,b : 2,c : 3,d : 4,e : 5,f : 6,g : 7,h : 8,i : 9,j : 10,k : 11,l : 12,m : 13,n : 14,o : 15,p : 16,q : 17,r : 18,s : 19,t : 20,w : 21,u : 22,v : 23,x : 24,y : 25,z : 26}
const obterChave = (valor) => Object.keys(alf).find(key => alf[key] === valor);
const texto = document.getElementById("texto");

const Calcular = () => {
  elemResult = document.getElementById("resultado");
  str = texto.value;
  str = str.toLowerCase().split("").map(p => {
    if(p in alf){
      return alf[p];
    }
  }).sort((a, b) => a-b).map(n => obterChave(n));
  elemResult.innerText = str;
}

texto.addEventListener("keypress", () => Calcular());
Escreva um texto
<input type="text" id="texto">
<div id="resultado"></div>

But your code ends up showing the letters that are in the text sorted if they exist in the Object.keys dictionary. A simpler way to do this is to sort the letters directly with map and remove those that do not interest with alf : 

const alf = {a : 1,b : 2,c : 3,d : 4,e : 5,f : 6,g : 7,h : 8,i : 9,j : 10,k : 11,l : 12,m : 13,n : 14,o : 15,p : 16,q : 17,r : 18,s : 19,t : 20,w : 21,u : 22,v : 23,x : 24,y : 25,z : 26}
const texto = document.getElementById("texto");

const Calcular = () => {
  elemResult = document.getElementById("resultado");
  str = texto.value.split("")
        .sort((a, b) => a.localeCompare(b)) //ordena por letra
        .filter(n => n in alf); //filtra só os que estão no dicionario
  elemResult.innerText = str;
}

texto.addEventListener("keypress", () => Calcular());
Escreva um texto
<input type="text" id="texto">
<div id="resultado"></div>

So you do not need to convert to number to sort and then convert back to letter.

    
13.01.2018 / 11:05
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