Home / Questions / 294113
Accepted
RazerJs
Asked: 2020-09-17 08:00:04 +0800 CST 2020-09-17 08:00:04 +0800 CST

Hyphenate the odd digits of a number

  • 772

I am trying to make a javascript function that, given a number n , separates its odd digits from the pairs with the character '-'.. if they are 2 consecutive pairs they are not separated, consecutive odd ones are separated ..

Ex1: function separarImpares(24589) ->(24-5-8-9)

Ex2: function separarImpares(132479) ->(1-3-24-7-9)

I put a code example of what I have tried. Thanks.

function separarImpares(num) {
    let str="";
    num = `${num}`.split('');    
    for(var i=0; i<num.length; i++){
        switch (num[i]) {
            case (num[i]%2==0 & num[i+1]%2!=0 ):
                str+=`${num[i]}-`;
                console.log(num[i]);  
                break;
            case (num[i]%2!=0 & num[i+1]%2!=0):
                str+=`${num[i]}-`;
                break;
            case (num[i]%2!=0 & num[i+1]%2==0):
                str+=`${num[i]}-`;
                break;
            default:
                str+=`${num[i]}`
                break;
      }
    }
    return str
}

console.log(separarImpares(6815))

javascript

3 Answers

  1. Using a regular expression split()would be a totally different approach and reduces the code a bit:

    const num = 2458936;

const res = `${num}`.split(/([13579])/g).slice(0,-1).join("-").replace(/--/g, '-');

console.log(res);

    Iterating, I would use [...'${num}']to pass from number to array and then %2for each number:

    const num = 2458936;

const res = [...`${num}`].map((e,i,a)=>(e%2)?(i<a.length -1)?`-${e}-`:`-${e}`:e).join("").replace(/--/g, '-');

console.log(res);

    • 4
  2. Best Answer

    I can propose 2 approaches on how to solve it in a very simplified way:

    1. You can iterate through the number and ask digit by digit if it is odd or not, then accumulate the result in a string:

    function separarImpares (num, nsi=''){
  num = num.toString().split('').map(i => i%2 ? nsi+=`-${i}-` : nsi+=i);
  return nsi.split('-').filter(String).join('-')
}
console.log(separarImpares(24598513067));

    It is used toString()to pass the number to a string, then split('')to divide the number and map()to go through the array and accumulate the digits in a string ( nsi) that will then be returned as a result.

    To remove the excess dashes and those at the beginning and end of the result you can use:

    split('-').filter(String).join('-')

    2. You can loop through an array of odd numbers by replacing each odd digit in the string with the same one with hyphens using split()and join():

    function separarImpares (num, n=[1,3,5,7,9]){
  n.map(i => num = num.toString().split(i).join(`-${i}-`));
  return num.split('-').filter(String).join('-');
}
console.log(separarImpares(24598513067));

    The same function is used to remove excess hyphens. Although this method could be less optimal, there is another way to solve it. Greetings.

    • 2

  3. Taking from the 2 answers I also made this function and I share it... thanks to @Emeeus and @the-breaker..

    function separarImpares(num) {
    return `${num}`.split(/([13579])/g).filter(String).join('-')
}

console.log(separarImpares(6815297))

    Another thing... if the number is negative odd then there would be a '--'at the beginning of the number and if it is negative even it would be negative (a '-') something that may not interest you if you are treating the number as a string to be separated, this would be easier depends on what you want to do (leave it negative without the double -- or the first negative even number which you can do with a replace('--', '-)))

    Show as a string 

    function separarImpares(num) {
    (num<0) ? num=num*-1 :null
      return `${num}`.split(/([13579])/g).filter(String).join('-');
    };

console.log(separarImpares(-18185))

    • 1