JS Equivalent to Python Format

In Python, the format() method is a powerful and flexible way to format strings. It allows us to embed expressions inside string literals. JavaScript does not have a direct equivalent to Python's format() method, but it offers several ways to achieve similar functionality. In this article, we will explore how to replicate the behavior of Python's format() method in JavaScript.

What is Python's format() Method?

Python's format() method is used to format strings by embedding variables and expressions within string literals. The method can be called on a string and takes arguments that are replaced in the string according to the placeholders provided.

Example:

name = "Shivang"
age = 22
s = "Name - {} and age - {} years".format(name, age)
print(s)

Name - Shivang and age - 22 years

Explanation:

• As seen in the example, the format() method replaces the placeholders {} with the corresponding arguments.

JavaScript Equivalent to Python Format

Below are the methods and approaches by which we can see the equivalence of Python and JavaScript format method:

Using Template Literals (Backticks)

The most common way to achieve similar functionality in JavaScript is by using template literals, which allow embedding expressions within strings using ${}.

Example:

const name = "Shivang";
const age = 22;

const s = `Name - ${name} and Age - ${age}`;
console.log(s);

Name - Shivang and Age - 22

Explanation:

• Template literals are wrapped in backticks (\``) and can include placeholders${}` where expressions or variables are evaluated and embedded directly within the string.

Using the + Operator for String Concatenation

Before template literals were introduced in ES6, the most often used operator was + operator to concatenate strings.

Example:

const name = "Shivang";
const age = 22;

const s = "Name - " + name + " and age - " + age + ".";
console.log(s);

Name - Shivang and age - 22.

Explanation:

• This method manually concatenates strings using the + operator. While it works, it can be less readable compared to template literals.

Using External Libraries

For more complex formatting needs, external libraries like sprintf-js be used.

Example:

const sprintf = require("sprintf-js").sprintf;
const name = "Shivang";
const age = 22;

const s = sprintf("Name - %s and age - %d .", name, age);
console.log(s);

Output:

Name - Shivang and age - 22 .

Explanation:

• The sprintf-js library allows for Python-like string formatting using placeholders like %s for strings and %d for numbers.
• This method is useful for more complex string formatting needs.