Regex in javascript to replace decimal to a secret text code

Question

I'm trying to write a simple function that converts currency values to a code.

I've managed to do the conversion part with .replace(). See jsfiddle https://jsfiddle.net/j9cdrq73/3/

What I want to do is, replace the 2nd repeating character(s) with letter 'Z'

Edit

After the dot (. decimal point) it should reset. 50000 DIZZZ.IZ NOTE the last IZ* see following examples

        number   => after convert =>final (what it should give)
       ---------    -------------  ----------------------------
 So      50000    =>  DI,III.II  =>  DI,ZZZ.IZ
       2677.99    =>   B,EFF.HH  =>   B,EFZ.HZ
     366666.22    => CEE,EEE.BB  => CEZ,ZZZ.BZ

Current code

    function number_to_code(s) {

    // converting the value to something like 50000.00 to look like currency
    // next replace it with the codes as bellow.

      s = parseFloat(s).toFixed(2).replace(/\d/g, m => ({
        '0': 'I',
        '1': 'A',
        '2': 'B',
        '3': 'C',
        '5': 'D',
        '6': 'E',
        '7': 'F',
        '8': 'G',
        '9': 'H'
      })[m]); 
    
    
    // grouping it with , 
      s = s.replace(/\B(?=(\w{3})+(?!\w))/g, ",");       
     return s;
    }

Better if we can do it all in a single regex to improve efficiency.

50000 be DI,ZZZ.IZ ANY repeating letter with Z but after the dot it rests again so agin shows the I — Hirantha, Jun 01 '21 at 08:59
@Hirantha Your sample output says `DI,IZZ.IZ` so it confuses people. — Hao Wu, Jun 01 '21 at 09:10
But if `50000` has to become `DI,ZZZ.IZ` then this `What I want to do is, replace the 2nd repeating character(s) with letter Z` does not apply right? — The fourth bird, Jun 01 '21 at 09:12
`50000.00` -> `DIIII.II` -> `DIZZZ.IZ` -> `DI,ZZZ.IZ`. What did I miss here? — Hao Wu, Jun 01 '21 at 09:17
@HaoWu Sorry my bad. I've fixed the confutation. Seems like both your answers work now. thank you. — Hirantha, Jun 01 '21 at 09:30
@Thefourthbird Yes. I just fixed the confusion. your solution too works fine now. thank you. — Hirantha, Jun 01 '21 at 09:31
@Thefourthbird could you look at this https://stackoverflow.com/questions/68042544/convert-a-javascript-regexp-function-to-a-php I want the same function in php too. thank you. — Hirantha, Jun 19 '21 at 00:04
@HaoWu could you look at this https://stackoverflow.com/questions/68042544/convert-a-javascript-regexp-function-to-a-php I want the same function in php too. thank you. — Hirantha, Jun 19 '21 at 00:04

The fourth bird · Accepted Answer · 2021-06-01T09:32:10.163

You might use 2 capture groups, with a backreference repeating the char 1 or more times that was captured in group 1.

([A-Z])(\1+)

([A-Z]) Capture group 1, match a char A-Z
(\1+) Capture group 2, repeat 1+ the same char that is captured in group 1

Regex demo

In the code, you can add another replacement returning the concatenation of group 1 followed by replacing all the characters with Z from group 2.

function number_to_code(s) {

  // converting the value to something like 50000.00 to look like currency
  // next replace it with the codes as bellow.

  s = parseFloat(s).toFixed(2).replace(/\d/g, m => ({
    '0': 'I',
    '1': 'A',
    '2': 'B',
    '3': 'C',
    '5': 'D',
    '6': 'E',
    '7': 'F',
    '8': 'G',
    '9': 'H'
  })[m]);

  // grouping it with , 
  s = s
    .replace(/([A-Z])(\1+)/g, (_, g1, g2) => {
      return g1 + g2.replace(/./g, "Z")
    })
    .replace(/\B(?=(\w{3})+(?!\w))/g, ",")

  return s;
}

console.log(number_to_code("50000"));
console.log(number_to_code("2677.99"));
console.log(number_to_code("366666.22"));

Thanks for the fast reply. but I want to keep first letter same and other repeating letters to be replaced. do the same after the (.) (decimal point). DIIIIIIII will look like DIZZZZZZ.IZ — Hirantha, Jun 01 '21 at 08:55
@Hirantha You can do the replacement of the repeating characters first in that case. See the updated answer. — The fourth bird, Jun 01 '21 at 09:26

score 0 · Answer 2 · answered Jun 01 '21 at 09:04

(\d)(\1*)

Maybe this is what you want.

The first group is any digit, the second groups is the repeated digits(if any). Then you replace them separately.

After that group the entire result with ,.

function number_to_code(s) {
  return parseFloat(s).toFixed(2)
    .replace(/(\d)(\1*)/g, (_, digit, repeats) => ({
      '0': 'I',
      '1': 'A',
      '2': 'B',
      '3': 'C',
      '5': 'D',
      '6': 'E',
      '7': 'F',
      '8': 'G',
      '9': 'H'
    })[digit] + ''.padStart(repeats.length, 'Z'))
    .replace(/\B(?=(\w{3})+(?!\w))/g, ",");
}

const numbers = [
  '50000',
  '2677.99',
  '366666.22',
];

const result = numbers.map(number_to_code);

console.log(result);

Wow that works.. let me play with it little more and digest the coding. :) — Hirantha, Jun 01 '21 at 09:16

Regex in javascript to replace decimal to a secret text code

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2 Answers2