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

JavaScript Basic: Exercise-68 with Solution

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

Pictorial Presentation:

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

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JavaScript program to create a new string using the first and last n characters from a given string. The string length must be greater or equal to n.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function two_string(str, n)
  {
    first_part = str.substring(0, n);
    last_part = str.substring(str.length - n);
    return first_part + last_part;
 }

console.log(two_string("JavaScript", 2));
console.log(two_string("JavaScript", 3));

Sample Output:

Japt
Javipt

Flowchart:

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

ES6 Version:

function two_string(str, n)
  {
    first_part = str.substring(0, n);
    last_part = str.substring(str.length - n);
    return first_part + last_part;
 }

console.log(two_string("JavaScript", 2));
console.log(two_string("JavaScript", 3));

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.


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Previous: Write a JavaScript program to create a new string from a given string, removing the first and last characters of the string if the first or last character are 'P'.
Next: Write a JavaScript program to compute the sum of three elements of a given array of integers of length 3.

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JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925 

Output:

385
3025
2925