hello I have values like this

1-10
2-3
901-321

I want to get the reverse values for example like this

10-1
3-2
321-901

I have tried this

  var str = "1-18";
 var newString = "";
    for (var i = str.length - 1; i >= 0; i--) {
        newString += str[i];
    }
    return newString;

But it gives me 81-1

hello I have values like this

1-10
2-3
901-321

I want to get the reverse values for example like this

10-1
3-2
321-901

I have tried this

  var str = "1-18";
 var newString = "";
    for (var i = str.length - 1; i >= 0; i--) {
        newString += str[i];
    }
    return newString;

But it gives me 81-1

• javascript
• node.js

5 Answers 5

Instead, use String.split(), Arrary.reverse() and Arrary.join():

var str = '901-321';

var strArray = str.split('-'); // ['901', '321']

var strArrayReversed = strArray.reverse(); // ['321', '901']

var result = strArrayReversed.join('-'); // '321-901'

console.log('result = ', result);

// You can do all these steps above in one go as:

var result2 = str.split('-')
  .reverse()
  .join('-');
  
console.log('result2 = ', result2);

MDN Docs:

• String.prototype.split()
• Array.prototype.reverse()
• Array.prototype.join()

Can split on the - to create array , reverse the array and join it back into string

var str = "1-18",
    newStr = str.split('-').reverse().join('-');

console.log(newStr)

a = "12-5"
console.log(a.split('-').reverse().join('-'))

You can use the split method to divide the string in two, and then use the second part before the first, like this:

var str = "1-18";
var l = str.split("-");
return l[1] + "-" + l[0];

You could replace the string by swapping the values.

var string = '901-321';

console.log(string.replace(/(.+)-(.+)/, '$2-$1'));