Data Types in Go

Data types define the kind of data a variable can store. Go is a statically typed language, meaning every variable has a fixed type that is checked at compile time.

Understanding data types is essential for writing correct, efficient, and safe Go programs.

Why Data Types Matter

Data types help Go:

• Allocate the correct amount of memory
• Prevent invalid operations
• Improve program performance
• Catch errors before execution

Go will not allow mixing incompatible types without explicit conversion.

Categories of Data Types in Go

Go data types can be broadly grouped into:

• Numeric types
• Boolean type
• String type
• Derived types (arrays, slices, maps, structs)

In this lesson, we focus on the core built-in data types.

Integer Types

Integers store whole numbers (no decimals). Go provides different integer sizes for efficiency and precision.

• int
• int8, int16, int32, int64
• uint, uint8, uint16, uint32, uint64

Example using real numeric values:

var users int = 150
var population int64 = 7800000000

Use:

• int for general-purpose counting
• int64 for very large numbers

Floating-Point Types

Floating-point numbers store decimal values. Go supports two floating types:

• float32
• float64 (default and recommended)

Example:

price := 29.99
interestRate := 7.5

Go infers both variables as float64.

Boolean Type

The bool type represents logical values. It can store only:

• true
• false

Example using a real-world condition:

isLoggedIn := true
hasSubscription := false

Boolean values are heavily used in decision-making and control flow.

String Type

Strings store text data and are enclosed in double quotes. Strings in Go are immutable (cannot be changed once created).

name := "Dataplexa"
city := "San Jose"

Strings are commonly used for:

• User names
• Messages
• File paths
• URLs

Using Multiple Data Types Together

A real program often uses multiple data types together.

package main

import "fmt"

func main() {
    username := "Alex"
    age := 28
    balance := 1540.75
    active := true

    fmt.Println("User:", username)
    fmt.Println("Age:", age)
    fmt.Println("Balance:", balance)
    fmt.Println("Active:", active)
}

Each variable has a different data type, and Go manages them safely.

Type Safety in Go

Go does not allow mixing types without explicit conversion.

This will cause an error:

// invalid
total := 10 + 2.5

Correct version:

total := float64(10) + 2.5

This strict behavior prevents hidden bugs.

Zero Values for Data Types

If a variable is declared without initialization, Go assigns a zero value:

• int → 0
• float64 → 0.0
• bool → false
• string → ""

Example:

var count int
var status bool
fmt.Println(count, status)

Real-World Example

In an e-commerce system:

• productName → string
• price → float64
• stock → int
• available → bool

Choosing the correct data type ensures accuracy and performance.

Practice Exercise

Task

Create variables for:

• Total students (int)
• Average score (float)
• Passed exam (bool)
• Course name (string)

Print all values using fmt.Println().

What You Will Learn Next

In the next lesson, you will learn about constants and iota, which are used for fixed values and enumerations in Go programs.