Types in Golang

Golang has a lot of data types. If you programmed in other languages before, you may be familiar with int, float or byte.

Data types can be grouped into 3 types: bool, numeric types and string

Of numeric types there are a lot!

• int8, int16, int32, int64, int
• uint8, uint16, uint32, uint64, uint
• float32, float64
• complex64, complex128
• byte
• rune

I'll explain some below.

Integers

In Golang, things work a bit differently. You can't just define an integer int, you have to specify the number of bits: int8,int16,int32,int64

Integers by default can have negative values, for positive only you need uint8, uint16, uint32 or uint64.

package main

import "fmt"

func main() {  
    var a int = 19
    b := 36
    fmt.Println("a is", a, " b is", b)
}

Floats

For floats, you have float32 and float64. You can define more than one float on one line. Go needs := to assign, not just =. A semicolon at the end of the statement is not required.

package main

import (  
    "fmt"
)

func main() {  
    a, b := 1.5, 8.5
    fmt.Printf("a %f b %f\n", a, b)
}

This outputs:

a 1.500000 b 8.500000

Program exited.

For less digits after the dot, use %.2f, %.3f etc.

fmt.Printf("a %.2f b %.2f\n", a, b)

Booleans

There's bool, which is True or False. This may be familiar. This is perhaps the only data type which is similar in all programming languages.

In short: only two values are possible, True (1/high) or False (0/low).

a := false
b := true   
fmt.Println("a:", a, "b:", b)

Related links:

• Learn Golang
• Go playground