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JavaScript: Create new string with first 3 characters are in lower case

JavaScript Basic: Exercise-37 with Solution

Write a JavaScript program to create a new string with first 3 characters are in lower case from a given string. If the string length is less than 3 convert all the characters in upper case.

Pictorial Presentation:

JavaScript: Create new string with first 3 characters are in lower case

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JavaScript program to create new string with first 3 characters are in lower case from a given string. If the string length is less than 3 convert all the characters in upper case.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function upper_lower(str) {
  if (str.length < 3) {
    return str.toUpperCase();
  }
  front_part = (str.substring(0, 3)).toLowerCase();
  back_part = str.substring(3, str.length);  
  return front_part + back_part;
}
console.log(upper_lower("Python"));
console.log(upper_lower("Py"));
console.log(upper_lower("JAVAScript"));

Sample Output:

python
PY
javAScript

Flowchart:

Flowchart: JavaScript - Create new string with first 3 characters are in lower case

ES6 Version:

function upper_lower(str) {
  if (str.length <= 3) {
    return str.toUpperCase();
  }
  front_part = (str.substring(0, 3)).toLowerCase();
  back_part = str.substring(3, str.length);  
  return front_part + back_part;
}
console.log(upper_lower("Python"));
console.log(upper_lower("Py"));
console.log(upper_lower("JAVAScript"));

Live Demo:

See the Pen JavaScript: check if the last digit of the three given positive integers is same - basic-ex-36 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

Classes/function constructors

class Person {
  constructor() {
    this.name = 'Owen';
  }
}

Person = class AnotherPerson {
  constructor() {
    this.name = 'Eddie';
  }
};

const member = new Person();
console.log(member.name);

We can set classes equal to other classes/function constructors. In this case, we set Person equal to AnotherPerson. The name on this constructor is Eddie, so the name property on the new Person instance member is "Eddie".

Ref: https://bit.ly/3jFRBje