JavaScript: Create a new string taking the first and last n characters from a given string

JavaScript Basic: Exercise-68 with Solution

Use First and Last 'n' Characters from String

Write a JavaScript program to create a new string using the first and last n characters from a given string. The string length must be larger than or equal to n.

The program takes a string and an integer n, then constructs a new string using the first n characters and the last n characters from the original string. It ensures the string's length is at least n before performing this operation.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named two_string with parameters str and n
function two_string(str, n) {
    // Extract the first part of the string from index 0 to n (exclusive)
    first_part = str.substring(0, n);
    // Extract the last part of the string from (length - n) to the end
    last_part = str.substring(str.length - n);
    // Concatenate the first and last parts and return the result
    return first_part + last_part;
}

// Call the function with sample arguments and log the results to the console
console.log(two_string("JavaScript", 2));
console.log(two_string("JavaScript", 3));

Output:

Japt
Javipt

Live Demo:

See the Pen Create a new string taking the first and last n characters from a given string by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

 // Define a function named two_string with parameters str and n
const two_string = (str, n) => {
    // Use const for constant variables and template literals for string concatenation
    const first_part = str.substring(0, n);
    const last_part = str.substring(str.length - n);
    return `${first_part}${last_part}`;
};

// Call the function with sample arguments and log the results to the console
console.log(two_string("JavaScript", 2));
console.log(two_string("JavaScript", 3));

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