JavaScript: Create a new string from a given string taking the last 3 characters and added at both the front and back

Last update on May 30 2022 09:56:30 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-26 with Solution

Write a JavaScript program to create a new string from a given string taking the last 3 characters and added at both the front and back. The string length must be 3 or more.

Pictorial Presentation:

JavaScript: Create a new string from a given string taking the last 3 characters and added at both the front and back

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 from a given string taking the last 3 characters and added at both the front and back. The string length must be 3 or more.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function front_back3(str)
 {
  if (str.length>=3)
   {
   str_len = 3;
 
  back = str.substring(str.length-3);
   return back + str + back;
 }
   else
     return false;
 }
console.log(front_back3("abc"));
console.log(front_back3("ab"));
console.log(front_back3("abcd"));

Sample Output:

abcabcabc
false
bcdabcdbcd

Flowchart:

ES6 Version:

function front_back3(str)
 {
  if (str.length>=3)
   {
   str_len = 3;
 
  back = str.substring(str.length-3);
   return back + str + back;
 }
   else
     return false;
 }
console.log(front_back3("abc"));
console.log(front_back3("ab"));
console.log(front_back3("abcd"));

Live Demo:

See the Pen JavaScript: added characters added at both the front and back-basic- ex-25 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04