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

JavaScript Basic: Exercise-21 with Solution

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

Pictorial Presentation:

JavaScript: Create a new string adding

Sample Solution:

JavaScript Code:

 // Define a function named string_check that takes a parameter str1
function string_check(str1) {
  // Check if str1 is null, undefined, or starts with the substring 'Py'
  if (str1 === null || str1 === undefined || str1.substring(0, 2) === 'Py') {
    // If true, return str1
    return str1;
  }
  // If false, prepend 'Py' to str1 and return the result
  return "Py" + str1;
}

// Log the result of calling the string_check function with the argument "Python" to the console
console.log(string_check("Python"));

// Log the result of calling the string_check function with the argument "thon" to the console
console.log(string_check("thon"));


Sample Output:

Python
Python

Live Demo:

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


Flowchart:

Flowchart: JavaScript - Create a new string adding

ES6 Version:

 // Using ES6 arrow function syntax to define the string_check function
const string_check = (str1) => (str1 === null || str1 === undefined || str1.substring(0, 2) === 'Py' ? str1 : `Py${str1}`);

// Log the result of calling the string_check function with the argument "Python" to the console
console.log(string_check("Python"));

// Log the result of calling the string_check function with the argument "thon" to the console
console.log(string_check("thon"));

Previous: JavaScript program to check from two given integers, if one is positive and one is negative.
Next: JavaScript program to remove a character at the specified position of a given string and return the new string.

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