CODEWITHSUNDEEP
javascriptpalindrome
Hacene .N
Hacene .N

Reputation: 115

Palindrome issue with JavaScript

I need to write a code with a function that has a parameter str that evaluates if the word is a palindrome or not, it should return true, else ir should return false.

Note: I need to remove all non-alphanumeric characters.

I wrote the code below but it is giving the opposite of the result expected:

console.log result

Code: 

function palindrome(str) {
  var exc = /[^\w_]/gi;
  var repStr = str.toLowerCase().replace(exc, "");
  console.log("Replaced string id: " + repStr);
  len = repStr.length -1

  for (var i = 0; i <= len; i++) {
    if (str[i] !== repStr[len] - i) {
      return false;
    }
  }
  return true;
}

console.log(palindrome("eye"));
console.log(palindrome("_eye"));
console.log(palindrome("race car"));
console.log(palindrome("not a palindrome"));
console.log(palindrome("A man, a plan, a canal. Panama"));
console.log(palindrome("never odd or even"));
console.log(palindrome("nope"));
console.log(palindrome("almostomla"));
console.log(palindrome("My age is 0, 0 si ega ym"));
console.log(palindrome("1 eye for of 1 eye."));
console.log(palindrome("0_0 (: /-\ :) 0-0"));
console.log(palindrome("five|\_/|four"));

Upvotes: 0

Views: 145

Answers (3)

Stefan Octavian
Stefan Octavian

Reputation: 620

There are 2 mistakes in your code. 1) the RegExp is not replacing the underscore as [^\w_] reads as "everything that is not a word character OR an underscore". Try

/[\W_]/g

which reads as "one of the following: any character that is not a word character, underscores"

OR

/[^0-9a-z]/g

which reads as "anything that is not: digits (from 0 to 9), english alphabet letters".

2) For it to work you need to write

if(repStr[i] !== repStr[len - i])

instead of

if(str[i] !== repStr[len] - i)

Upvotes: 1

Carloluis
Carloluis

Reputation: 4320

Try this out:

function palindrome(str) {
    const letters = str.replace(/[^a-z]/gi, ''); // replace any char that is not in the set [a-z] range
    const lowercase = letters.toLowerCase();
    const reversed = lowercase.split('').reverse().join('');
    return lowercase === reversed;
}

Upvotes: 0

Aswin Ramesh
Aswin Ramesh

Reputation: 1674

you can simply replace the two of your lines

for (var i = 0; i <= len; i++, len--) {
    if (str[i] !== repStr[len]) {

check this

function palindrome(str) {
  var exc = /[^\w_]/gi;
  var repStr = str.toLowerCase().replace(exc, "");
  console.log("Replaced string id: " + repStr);
  len = repStr.length -1

  for (var i = 0; i <= len; i++, len--) {
    if (str[i] !== repStr[len]) {
      return false;
    }
  }
  return true;
}

console.log(palindrome("eye"));
console.log(palindrome("_eye"));
console.log(palindrome("race car"));
console.log(palindrome("not a palindrome"));
console.log(palindrome("A man, a plan, a canal. Panama"));
console.log(palindrome("never odd or even"));
console.log(palindrome("nope"));
console.log(palindrome("almostomla"));
console.log(palindrome("My age is 0, 0 si ega ym"));
console.log(palindrome("1 eye for of 1 eye."));
console.log(palindrome("0_0 (: /-\ :) 0-0"));
console.log(palindrome("five|\_/|four"));

Upvotes: 0

Related Questions