Basic Data Types

Go has basic data types including integers, floating-point numbers, strings, and booleans. Each type has a clearly defined size and purpose.

Syntax List

Type	Description
int / int8 / int16 / int32 / int64	Signed integer types. `int` is platform-dependent and is 64-bit on 64-bit environments.
uint / uint8 / uint16 / uint32 / uint64	Unsigned integer types. They cannot hold negative values, but their positive range is twice that of signed types.
float32 / float64	Floating-point number types. Use `float64` for higher precision in most cases.
complex64 / complex128	Complex number types. Each value has a real part and an imaginary part.
string	A string type. It is an immutable sequence of bytes encoded in UTF-8.
bool	A boolean type. Its value is either `true` or `false`.
byte	An alias for `uint8`. Used when working with raw byte data.
rune	An alias for `int32`. Represents a Unicode code point (a single character).

Sample Code

sample_basic_types.go

package main

import "fmt"

func main() {
	// Integer types
	var age int = 25
	var score int64 = 9876543210

	// Floating-point types
	var price float64 = 1980.5
	var ratio float32 = 3.14

	// String type
	var name string = "Itadori Yuji"
	greeting := "Hello, " + name + "!"

	// Boolean type
	var isActive bool = true

	// byte and rune
	var b byte = 'A' // ASCII code 65
	var r rune = 'é' // Unicode code point U+00E9

	fmt.Println(age, score)
	fmt.Printf("%.1f / %.2f\n", price, ratio)
	fmt.Println(greeting)
	fmt.Println(isActive)
	fmt.Printf("byte: %d, rune: %d\n", b, r)

	// String length in bytes vs. number of characters
	s := "café"
	fmt.Println(len(s)) // Byte length: 5 (é is 2 bytes in UTF-8)
	fmt.Println(len([]rune(s))) // Character count: 4
}

This produces the following output:

go run basic_types.go
25 9876543210
1980.5 / 3.14
Hello, Itadori Yuji!
true
byte: 65, rune: 233
5
4

Notes

Go's integer types include those with an explicit size and the platform-dependent int. In most cases int is sufficient, but specifying an explicit size is important when doing binary operations or communicating with external APIs.

Because string is a byte sequence, len() returns the byte count for multibyte characters such as accented letters or emoji. To work with the correct character count, convert the string to []rune(s) first.

Type conversion is never implicit in Go, so arithmetic between different types requires an explicit type conversion.

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Go Dictionary

Basic Data Types

Syntax List

Sample Code

sample_basic_types.go

Notes