how do I insert dashes between each two even digits of a specific number

Question

I am trying to insert dash(-) between two even numbers. Problem is dashes don't locate between two even numbers but at the end of the number.

here is the code

function insertHyphen(str) {
  var strArr = str.split('');
  var numArr = strArr.map(Number);
  for(var i = 0; i < numArr.length; i++) {
   if(numArr[i-1]%2===0 && numArr[i]%2===0) {
        numArr.push('-');
    }
  }
  return numArr.join('');
}
insertHyphen('112233445566'); // 112233445566---

See https://stackoverflow.com/questions/586182/how-to-insert-an-item-into-an-array-at-a-specific-index — Daut, Sep 25 '18 at 08:50

Daut · Answer 1 · 2019-02-01T14:14:34.383

3

Use splice() instead of push(). See here Splice MDN

function insertHyphen(str) {
  var strArr = str.split('');
  var numArr = strArr.map(Number);
    for(var i = 0; i < numArr.length; i++) {
      if(numArr[i-1]%2===0 && numArr[i]%2===0) {
        numArr.splice(i, 0, '-');
      }
    }
  return numArr.join('');
}
console.log(insertHyphen('112233445566')); // 112-2334-4556-6

edited Feb 01 '19 at 14:14

answered Sep 25 '18 at 08:47

Daut

2,537
1
19
32

score 3 · Answer 2 · answered Sep 25 '18 at 08:50

3

Using regex:

var p = '112233445566';

var regex = /([02468])([02468])/g

console.log(p.replace(regex, '$1-$2'));

Try it online: https://tio.run/##y0osSyxOLsosKNHNy09J/f@/LLFIoUDBVkHd0NDIyNjYxMTU1MxM3ZqLCyRRlJqeWgGU1NeINjAyMbOI1YQz9NO5uJLz84rzc1L1cvLTNQr0ilILchKTUzXAmnQU1FUMdVWM1DU1rbn@/wcA

answered Sep 25 '18 at 08:50

memo

1,868
11
19

1

Please provide executable code snippet here itself. – Pardeep Dhingra Sep 25 '18 at 08:53

score 1 · Accepted Answer · answered Sep 25 '18 at 08:56

1

replace

numArr.push('-');

with

numArr.splice(i, 0, '-');

answered Sep 25 '18 at 08:56

Vikash_Singh

1,856
2
14
27

Someone answered just that 9 minutes earlier - o.O – d0n.key Sep 25 '18 at 09:35

score 1 · Answer 4 · answered Nov 02 '20 at 06:29

function insertHyphen(str) {
  var strArr = str.split('');
  var numArr = strArr.map(Number);
    for(var i = 0; i < numArr.length; i++) {
      if(numArr[i-1]%2===0 && numArr[i]%2===0) {
        numArr.splice(i, 0, '-');
      }
    }
  return numArr.join('');
}
console.log(insertHyphen('025468 '));

score 1 · Answer 5 · answered Feb 01 '21 at 16:54

Convert number to String
keep first element of array into separate array i.e. newArray
Run the loop on string length
Check current and the next element is divisible by 2 or not. If yes, push '-' else push the next item.
Finally join the array elements of newArray with ''.


    let a = 224578;
    let str = a.toString()
    var newArray=[arr[0]]
    if(arr?.length > 0){
            
            for (let i = 0; i < arr.length; i++) {
                if(arr[i] % 2 === 0 && arr[i+1] % 2 === 0){
                    newArray.push('-', arr[i+1])
                } else{
                    newArray.push(arr[i+1])
                }
            }
        }

    console.log('newArray', newArray.join(''))

score 0 · Answer 6 · answered Sep 25 '18 at 08:47

Push inserts element at the end of the array. You can use splice to enter element at particular position.

arr.splice(index, 0, item);

Here index is the position where you want to insert item element. And 0 represents without deleting 0 elements.

function insertHyphen(str) {
  var strArr = str.split('');
  var numArr = strArr.map(Number);
  for(var i = 0; i < numArr.length; i++) {
   if(numArr[i-1]%2===0 && numArr[i]%2===0) {
        numArr.splice(i, 0, '-');
    }
  }
  return numArr.join('');
}

console.log(insertHyphen('112233445566'));

score 0 · Answer 7 · answered Sep 25 '18 at 08:53

A simple way:

function insertHyphen(str) {
  var strArr = str.split('');
  var numArr = strArr.map(Number);
  var result ="";
  for(var i = 0; i < numArr.length; i++) {
   if((numArr[i+1]!==undefined)&&(numArr[i]%2===0 && numArr[i+1]%2===0)) {
        //numArr.push('-');
        result = result + numArr[i] + "-";
    }else{
        result = result + numArr[i];
    }
  }
  return result;
}
console.log(insertHyphen('112233445566'));

score 0 · Answer 8 · answered Sep 25 '18 at 09:09

You could map the new string by check the value and predecessor.

function insertHyphen(string) {
    return Array
        .from(string, (v, i) => !i || v % 2 || string[i - 1] % 2 ? v : '-' + v)
        .join('');
}

console.log(insertHyphen('22112233445566'));

score 0 · Answer 9 · answered Aug 25 '19 at 12:57

Using push() method and single loop

let input = '346845';
let result = [input[0]], 
len = input.length;

for (var i = 1; i < len; i++) {
  if (input[i - 1] % 2 === 0 && input[i] % 2 === 0) {
    result.push('-', input[i]);
  } else {
    result.push(input[i]);
  }
}
console.log(result.join(''));

how do I insert dashes between each two even digits of a specific number

9 Answers9