This article presents a comparison between the syntax and fundamental programming constructs of JavaScript and Python. It aims to highlight similarities in how basic programming concepts are implemented across these two popular programming languages.
While both languages share many commonalities, making it easier for developers to switch between them or understand the other's code, there are also distinct syntactical and operational differences that one should be aware of.
It's important to approach this comparison with a light-hearted perspective and not to overemphasize the likeness or differences between JavaScript and Python. The intention is not to declare one language superior to the other but to provide a resource that can help coders who are familiar with Python to understand and transition to JavaScript more easily.
Hello World
JavaScript
// In codeguppy.com environment
println('Hello, World');
// Outside codeguppy.com
console.log('Hello, World');
Python
print('Hello, World')
Variables and Constants
JavaScript
let myVariable = 100;
const MYCONSTANT = 3.14159;
Python
myVariable = 100
MYCONSTANT = 3.14159
String Interpolation
JavaScript
let a = 100;
let b = 200;
println(`Sum of ${a} and ${b} is ${a + b}`);
Python
a = 100
b = 200
print(f'Sum of {a} and {b} is {a + b}')
If Expression / Statement
JavaScript
let age = 18;
if (age < 13)
{
println("Child");
}
else if (age < 20)
{
println("Teenager");
}
else
{
println("Adult");
}
Python
age = 18
if age < 13:
print("Child")
elif age < 20:
print("Teenager")
else:
print("Adult")
Conditionals
JavaScript
let age = 20;
let message = age >= 18 ? "Can vote" : "Cannot vote";
println(message); // Output: Can vote
Python
age = 20
message = "Can vote" if age >= 18 else "Cannot vote"
print(message) # Output: Can vote
Arrays
JavaScript
// Creating an array
let myArray = [1, 2, 3, 4, 5];
// Accessing elements
println(myArray[0]); // Access the first element: 1
println(myArray[3]); // Access the fourth element: 4
// Modifying an element
myArray[2] = 30; // Change the third element from 3 to 30
// Adding a new element
myArray.push(6); // Add a new element to the end
Python
# Creating a list to represent an array
my_array = [1, 2, 3, 4, 5]
# Accessing elements
print(my_array[0]) # Access the first element: 1
print(my_array[3]) # Access the fourth element: 4
# Modifying an element
my_array[2] = 30 # Change the third element from 3 to 30
# Adding a new element
my_array.append(6) # Add a new element to the end
ForEach
JavaScript
let fruits = ["apple", "banana", "cherry", "date"];
for(let fruit of fruits)
println(fruit);
Python
fruits = ["apple", "banana", "cherry", "date"]
for fruit in fruits:
print(fruit)
Dictionaries
JavaScript
// Creating a dictionary
fruit_prices = {
apple: 0.65,
banana: 0.35,
cherry: 0.85
};
// Accessing a value by key
println(fruit_prices["apple"]); // Output: 0.65
Python
# Creating a dictionary
fruit_prices = {
"apple": 0.65,
"banana": 0.35,
"cherry": 0.85
}
# Accessing a value by key
print(fruit_prices["apple"]) # Output: 0.65
Functions
JavaScript
function addNumbers(a, b)
{
return a + b;
}
let result = addNumbers(100, 200);
println("The sum is: ", result);
Python
def add_numbers(a, b):
return a + b
result = add_numbers(100, 200)
print("The sum is: ", result)
Tuple Return
JavaScript
function getCircleProperties(radius)
{
const area = Math.PI * radius ** 2;
const circumference = 2 * Math.PI * radius;
return [area, circumference]; // Return as an array
}
// Using the function
const [area, circumference] = getCircleProperties(5);
println(`The area of the circle is: ${area}`);
println(`The circumference of the circle is: ${circumference}`);
Python
import math
def getCircleProperties(radius):
"""Calculate and return the area and circumference of a circle."""
area = math.pi * radius**2
circumference = 2 * math.pi * radius
return (area, circumference)
# Using the function
radius = 5
area, circumference = getCircleProperties(radius)
print(f"The area of the circle is: {area}")
print(f"The circumference of the circle is: {circumference}")
Variable number of arguments
JavaScript
function sumNumbers(...args)
{
let sum = 0;
for(let i of args)
sum += i;
return sum;
}
println(sumNumbers(1, 2, 3));
println(sumNumbers(100, 200));
Python
def sum_numbers(*args):
sum = 0
for i in args:
sum += i
return sum
print(sum_numbers(1, 2, 3))
print(sum_numbers(100, 200))
Lambdas
JavaScript
const numbers = [1, 2, 3, 4, 5];
// Use map to apply a function to all elements of the array
const squaredNumbers = numbers.map(x => x ** 2);
println(squaredNumbers); // Output: [1, 4, 9, 16, 25]
Python
numbers = [1, 2, 3, 4, 5]
# Use map to apply a function to all elements of the list
squared_numbers = map(lambda x: x**2, numbers)
# Convert map object to a list to print the results
squared_numbers_list = list(squared_numbers)
print(squared_numbers_list) # Output: [1, 4, 9, 16, 25]
Classes
JavaScript
class Book
{
constructor(title, author, pages)
{
this.title = title;
this.author = author;
this.pages = pages;
}
describeBook()
{
println(`Book Title: ${this.title}`);
println(`Author: ${this.author}`);
println(`Number of Pages: ${this.pages}`);
}
}
Python
class Book:
def __init__(self, title, author, pages):
self.title = title
self.author = author
self.pages = pages
def describe_book(self):
print(f"Book Title: {self.title}")
print(f"Author: {self.author}")
print(f"Number of Pages: {self.pages}")
Usage of classes
JavaScript
// Creating an instance of the Book class
// This is actually a real book (see Curriculum section for more info)
const myBook = new Book("Illustrated JavaScript", "Adrian", 684);
myBook.describeBook();
Python
# Creating an instance of the Book class
# This is actually a real book (see Curriculum section for more info)
my_book = Book("Illustrated JavaScript", "Adrian", 684)
my_book.describe_book()
Conclusion
We encourage you to get involved in refining this comparison. Your contributions, whether they are corrections, enhancements, or new additions, are highly valued. By collaborating, we can create a more accurate and comprehensive guide that benefits all developers interested in learning about JavaScript and Python.
Credits
This article was republished from the blog of the free coding platform https://codeguppy.com platform.
The article was influenced by similar comparisons between other programming languages:
- Kotlin is like C# https://ttu.github.io/kotlin-is-like-csharp/
- Kotlin is like TypeScript https://gi-no.github.io/kotlin-is-like-typescript/
- Swift is like Kotlin https://nilhcem.com/swift-is-like-kotlin/
- Swift is like Go http://repo.tiye.me/jiyinyiyong/swift-is-like-go/
- Swift is like Scala https://leverich.github.io/swiftislikescala/
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