#Day28 - From Python to JavaScript - The Basics Part 1

I have worked with JavaScript previously but it's been almost 3 years since I have written any JavaScript Code. I have mostly been working with Python and I am all for Python. However, there is no denying that JavaScript is everywhere like EVERYWHERE. As I am re-learning JavaScript, I am going to document my experiences, in case anyone is in a similar boat (Learning JavaScript as a Python Developer).

We will be covering the following in this tutorial

• Why you should learn JavaScript
• How to Run JavaScript/Python and show output
• Variables
• Comments

Why JavaScript?

I have borrowed a Tweet from Danny Thompson and as you can see JavaScript is used almost everywhere. Although, not the most popular choice, it can be used for building Machine Learning Models as well. Additionally, it can also be used to build various bots for Twitter, Discord, LinkedIn, etc

How to run JavaScript/Python

The Easiest Way? Use an online tool like Replit. It supports both JavScript(Select NodeJS) and Python.

Python

We can use the terminal to run Python files.

python main.py

To display an output, we can use the print function

print("Hello World!")

Javascript

Either you can link a javascript file in an HTML file and open it using any modern browser. Or you could open your browser's developer tools

To display an output, we can use console.log()

console.log("Hello World!")

Variables

We will only consider the basic variables, i.e we won't be considering Lists, Tuples, Dictionaries, etc. We will discuss Lists, Tuples, etc in future articles.

Python

We use the following syntax to declare a variable in Python

variableName = value

In Python, we have the following basic variable types

• Integers

  variable_integer = 10
  

• Float

  variable_float = 9.8
  

• Boolean

  variable_boolean = True
  

• String

  variable_string = "HelloWorld"
  

• Although Python doesn't support constants, there is a naming convention to declare constants. Constants are named in all upper case letters

  PI = 3.14
  

• Python also supports None values.

  variable_None = None
  

JavaScript

There are a couple of ways to declare variables in JavaScript. JavaScript also supports constants but we will discuss that in a bit.

let variableName = value
var variableName = value

The keyword "let" is preferred over "var". Below are the basic data types in JavaScript

• Numbers

  let variable_number_integer = 10
  let variable_number_float = 9.8
  

  Unlike Python, JavaScript doesn't differentiate between float and integers.

• Boolean

  let variable_booelan = true
  

• Strings

  let variable_string = "HelloWorld"
  

• Unlike Python, JavaScript supports constants. They are immutable.

  const PI = 3.14
  

• Additionally, JavaScript also supports the types NULL and Undefined

  let variable_null = null
  let variable_undefined = undefined
  

  The null type in JavaScript is similar to the None type in Python

Comments

Python

• Single-Line Comments

  # This is a single line comment
  

• Multi-Line Comments

  '''
  This is a multi-line comment
  This is a multi-line comment
  '''
  

JavaScript

• Single-Line Comments

  // This is a single line comment
  

• Multi-Line Comments

  /*
  This is a multi-line comment
  This is a multi-line comment
  */
  

Summary