how to change to english number to nepali number in php

Question

I want to change the English numerals to Nepali one up to 2 digits. For example: if I enter 1 it should return १ and if I enter 41 it should return ४१ and I have to store ४१ in DB and show it in the front end. 
This is what I have done till now:

function convertNos($nos){
  switch($nos){
    case"०":return 0;
    case"१":return 1;
    case"२":return 2;
    case"३":return 3;
    case"४":return 4;
    case"५":return 5;
    case"६":return 6;
    case"७":return 7;
    case"८":return 8;
    case"९":return 9;
    case"0":return"०";
    case"1":return"१";
    case"2":return"२";
    case"3":return"३";
    case"4":return"४";
    case"5":return"५";
    case"6":return"६";
    case"7":return"७";
    case"8":return"८";
    case"9":return"९";
   }
}

Can someone help me solve this?