Determine the frequency of a specific letter in JavaScript by utilizing the indexOf method

Question

Determine the frequency of a specific letter in JavaScript by utilizing the indexOf method

Hey there! I'm currently working on a code to count the occurrences of a specific letter in a string using indexOf(). However, it seems like something may be off with my implementation. Can anyone point me in the right direction? Thanks!

var string = 'Lets find l as many times as we can. Love is natural, love you lots';

var myFunc = function (letter) {
    newString = 0;
    for (var i = 0; i < letter.length; i += 1) {
        if (string.indexOf('l')) {
            newString += 1;
        }
    }
    return newString;
}

javascript for-loop indexof

Answer 1

Answer №1

Try this method instead

if (string.indexOf('l')) {
    newString += 1;
}

Consider using charAt or direct indexing to evaluate each character in a string.

For example

if (letter[i] == 'l') {
    newString += 1;
}

or you can do it this way

if (letter.charAt(i) == 'l') {
    newString += 1;
}

Check out this FIDDLE for a demonstration

Keep in mind that if you decide to use indexOf, you should apply it directly on the specific string, like so

letter.indexOf('l')

Answer 2

Try this method instead

if (string.indexOf('l')) {
    newString += 1;
}

Consider using charAt or direct indexing to evaluate each character in a string.

For example

if (letter[i] == 'l') {
    newString += 1;
}

or you can do it this way

if (letter.charAt(i) == 'l') {
    newString += 1;
}

Check out this FIDDLE for a demonstration

Keep in mind that if you decide to use indexOf, you should apply it directly on the specific string, like so

letter.indexOf('l')

Answer 3

Answer №2

While the previous answer is adequate, if you are determined to utilize the indexOf method (based on your question's title), remember to include a second parameter to specify where to begin searching for the next instance:

const myFunction = function(str) {
    let index = 0, count = 0;
    do {
        index = str.indexOf('l', index);
    } while (++index && ++count);
    return count;
}

For a simpler solution without the constraint of using indexOf, consider this alternative:

const myFunction = function(str) {
    return str.split('l').length - 1;
}

Answer 4

While the previous answer is adequate, if you are determined to utilize the indexOf method (based on your question's title), remember to include a second parameter to specify where to begin searching for the next instance:

const myFunction = function(str) {
    let index = 0, count = 0;
    do {
        index = str.indexOf('l', index);
    } while (++index && ++count);
    return count;
}

For a simpler solution without the constraint of using indexOf, consider this alternative:

const myFunction = function(str) {
    return str.split('l').length - 1;
}

Answer 5

Answer №3

If you are determined to use the indexOf method, here is a recursive approach:

const countOccurences = function (str, letter) {
  let count = 0;
  let index = str.indexOf(letter);

  if (index > -1) {
    count += (1 + countOccurences(str.slice(index + 1), letter));
  }

  return count;
};

Here's a working demo on JSFiddle

Answer 6

If you are determined to use the indexOf method, here is a recursive approach:

const countOccurences = function (str, letter) {
  let count = 0;
  let index = str.indexOf(letter);

  if (index > -1) {
    count += (1 + countOccurences(str.slice(index + 1), letter));
  }

  return count;
};

Here's a working demo on JSFiddle

Determine the frequency of a specific letter in JavaScript by utilizing the indexOf method

Answer №1

Answer №2

Answer №3

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