JavaScript: Create a new string adding "Py" in front of a given string

Last update on May 30 2022 10:06:50 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-21 with Solution

Write a JavaScript program to create a new string adding "Py" in front of a given string. If the given string begins with "Py" then return the original string.

Pictorial Presentation:

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 adding “Py” in front of a given string.  If the given string begins with “Py” then return the original string.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function string_check(str1) {
  if (str1 === null || str1 === undefined || str1.substring(0, 2) === 'Py') 
  {
    return str1;
  }
  return "Py"+str1;
}

console.log(string_check("Python"));
console.log(string_check("thon"));

Sample Output:

Python
Python

Flowchart:

ES6 Version:

function string_check(str1) {
  if (str1 === null || str1 === undefined || str1.substring(0, 2) === 'Py') 
  {
    return str1;
  }
  return `Py${str1}`;
}

console.log(string_check("Python"));
console.log(string_check("thon"));

Live Demo:

See the Pen JavaScript: Create new string: basic-ex-21 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to remove a character at the specified position of a given string and return the new string.

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