function to check if string is the same reading from back removing commas and spaces, javascript-CodePudding

this function check if a string is the same if you read it from back to start and it returns true if it does and false if not. The function is working but I can not use it in a test because it contains "replaceAll" , so I need to modify using some sort of basic javascript without regexp or "replaceALL" / "split" / "join" etc. The function has to remove commas and empty spaces from the string also to lower its chars.

function reversible(target) {
  let lower = target.toLowerCase();
   let comma = lower.replaceAll(',','');
  let empty = comma.replaceAll(' ','');
  let result = '';
  for ( let i = empty.length - 1 ; i >= 0 ; i--){
    result  = empty[i];
    } 
  if (result === empty) {return true;}
  else{return false;}
}
console.log(reversible('rotator'));
console.log(reversible('home'));
console.log(reversible('Racecar'));
console.log(reversible('eva, can i see bees in a cave'))

CodePudding user response：

var reversible = function(string) {
  var trimmedString = string.replace(/[, ] /g, "").trim();
  var reverseString = trimmedString.split('').reverse().join('');
  return trimmedString == reverseString;
}

console.log(reversible('rotator'));
console.log(reversible('home'));
console.log(reversible('Racecar'));
console.log(reversible('eva, can i see bees in a cave'))

CodePudding user response：

This loops through half the string, ignoring spaces and commas, and checking that the letter at the beginning matches the letter at the end, and so on.

function reversible(target) {
  target = target.toLowerCase();
  const l = target.length;
  let i = 0;
  let j = l - 1;
  let output = "";
  let output2 = "";
  
  do {
    while (target[i] === " " || target[i] === ",") {
      i  ;
    }
    while (target[j] === " " || target[j] === ",") {
      j--;
    }
    if (i < j) {
      if (target[i] === target[j]) {
        output  = target[i];
        output2 = target[i]   output2;
        i  ;
        j--;
      } else {
        return "Not reversible";
      }
    }
  } while (i < j);
  
  if (i === j) {
    // odd number of letters
    return output   target[i]   output2;
  } else {
    return output   output2;
  }
}

console.log(reversible('rotator'));
console.log(reversible('home'));
console.log(reversible('Racecar'));
console.log(reversible('eva, can i see bees in a cave'))

CodePudding user response：

you can create a new string and use the method concat to add the string without commas or spaces

  function reversible(target) {
  let lower = target.toLowerCase();
  let empty=""
  for ( let i = 0 ; i <=lower.length-1 ; i  ){
    //if character different of "," or space
    if (lower[i]!==" " & lower[i] !== ","){
    //concatenate character
      empty=empty.concat(lower[i])
    }

    } 
  result=""
  for ( let i = empty.length - 1 ; i >= 0 ; i--){
    result  = empty[i];
    } 
  return result==empty[i]
}


console.log(reversible('rotator'));
console.log(reversible('home'));
console.log(reversible('Racecar'));
console.log(reversible('eva, can i see bees in a cave'))