JavaScript: Letter count within a string

JavaScript Function: Exercise-22 with Solution

Count Letter in String

Write a JavaScript function that accepts two arguments, a string and a letter and the function will count the number of occurrences of the specified letter within the string.

Sample arguments: 'w3resource.com', 'o'
Expected output: 2

Pictorial Presentation:

Sample Solution-1:

JavaScript Code:

// Define a function named char_count that counts the occurrences of a specified letter in a given string
function char_count(str, letter) {
    // Initialize a variable letter_Count to store the count of occurrences
    var letter_Count = 0;

    // Iterate through each position in the input string
    for (var position = 0; position < str.length; position++) {
        // Check if the character at the current position is equal to the specified letter
        if (str.charAt(position) == letter) {
            // If true, increment the letter_Count by 1
            letter_Count += 1;
        }
    }

    // Return the final count of occurrences
    return letter_Count;
}

// Log the result of calling char_count with the input string 'w3resource.com' and the letter 'o' to the console
console.log(char_count('w3resource.com', 'o')); 

Output:

2

Flowchart:

Live Demo:

See the Pen JavaScript - Letter count within a string-function-ex- 22 by w3resource (@w3resource) on CodePen.

Sample Solution-2:

JavaScript Code:

// Alternate function to count occurrences of a letter in a string
function countOccurrences(str, letter) {
    // Use split to convert the string into an array of characters
    const charArray = str.split('');

    // Use filter to create an array containing only the target letter
    const occurrencesArray = charArray.filter(char => char === letter);

    // Return the length of the occurrences array, which is the count of occurrences
    return occurrencesArray.length;
}

// Example usage:
const inputString = 'w3resource.com';
const targetLetter = 'o';
const resultCount = countOccurrences(inputString, targetLetter);

// Log the result to the console
console.log(resultCount); 

Output:

2

Flowchart:

For more Practice: Solve these Related Problems:

• Write a JavaScript function that counts the occurrences of a specific letter in a string in a case-insensitive manner.
• Write a JavaScript function that uses a loop to count how many times a given letter appears in a string.
• Write a JavaScript function that employs a regular expression to count the occurrences of a letter within a string.
• Write a JavaScript function that counts the occurrences of a letter and returns a custom message if the letter is not found.

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