JavaScript: Extract the first half of a string of even length

JavaScript Basic: Exercise-59 with Solution

Extract First Half of Even-Length String

Write a JavaScript program to extract the first half of a even string.

This JavaScript program takes an input string with an even number of characters and returns a new string containing only the first half of the original string.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named first_half with parameter str
function first_half(str) {
    // Check if the length of the string is even
    if (str.length % 2 == 0) {
        // Use the slice method to get the first half of the string
        return str.slice(0, str.length / 2);
    }
    // If the length is odd, return the original string
    return str;
}

// Call the function with sample arguments and log the results to the console
console.log(first_half("Python"));       // Outputs "Py"
console.log(first_half("JavaScript"));   // Outputs "Java"
console.log(first_half("PHP"));           // Outputs "PHP" 

Output:

Pyt
JavaS
PHP

Live Demo:

See the Pen JavaScript - Extract the first half of a string of even length - basic-ex-59 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

// Define a function named first_half with parameter str
const first_half = (str) => {
    // Check if the length of the string is even
    if (str.length % 2 === 0) {
        // Use slice to get the first half of the string
        return str.slice(0, str.length / 2);
    }
    // Return the original string if the length is odd
    return str;
};

// Call the function with sample arguments and log the results to the console
console.log(first_half("Python"));
console.log(first_half("JavaScript"));
console.log(first_half("PHP"));

For more Practice: Solve these Related Problems:

• Write a JavaScript program that checks if a string has an even number of characters and returns its first half, otherwise returns an error message.
• Write a JavaScript function that trims whitespace from an even-length string and then extracts its first half.
• Write a JavaScript program that verifies if a string is even in length and extracts the first half using substring methods.

Go to:

• JavaScript basic Exercises Home ↩
• JavaScript Exercises Home ↩

PREV : Four Copies of Last 3 Characters.
NEXT : Remove First and Last Characters in String.

Improve this sample solution and post your code through Disqus.