Numeric literal formats in Swift

Introduction

Numeric literals let you write numbers directly in your code. They help you tell the computer exact values to use.

When you want to assign a number to a variable or constant.

When you need to write numbers in different bases like binary or hexadecimal.

When you want to make large numbers easier to read by adding underscores.

When you want to specify floating-point numbers with decimals.

When you want to use scientific notation for very big or very small numbers.

Syntax

Swift

let decimal = 1234
let binary = 0b1001
let octal = 0o17
let hex = 0x1F
let floatNum = 12.34
let expNum = 1.2e3
let readableNum = 1_000_000

Numeric literals can be decimal, binary (start with 0b), octal (0o), or hexadecimal (0x).

Underscores (_) can be used inside numbers to improve readability without changing the value.

Examples

A simple decimal number.

Swift

let decimal = 42

A binary number representing 10 in decimal.

Swift

let binary = 0b1010

A hexadecimal number representing 255 in decimal.

Swift

let hex = 0xFF

Using underscores to make a large number easier to read.

Swift

let largeNumber = 1_000_000

Sample Program

This program shows different numeric literal formats in Swift and prints their decimal values.

Swift

import Foundation

let decimal = 100
let binary = 0b1100100
let octal = 0o144
let hex = 0x64
let floatNum = 123.45
let expNum = 1.2345e2
let readableNum = 1_000_000

print("Decimal: \(decimal)")
print("Binary: \(binary)")
print("Octal: \(octal)")
print("Hexadecimal: \(hex)")
print("Float: \(floatNum)")
print("Exponential: \(expNum)")
print("Readable number: \(readableNum)")

Important Notes

All numeric literals represent the same value regardless of format when printed as decimal.

Floating-point literals can use decimal points or exponential notation.

Underscores do not affect the value but help you read large numbers easily.

Summary

Numeric literals let you write numbers in decimal, binary, octal, or hexadecimal.

You can use underscores to make numbers easier to read.

Floating-point numbers can be written with decimals or scientific notation.