Zero values

Context

In Go, variables declared without an explicit initial value are automatically assigned a zero value. This is the default value for each type.

Type	Zero value
bool	false
numeric (int, float, etc.)	0
string	"" (empty string)
pointers, slices, maps, channels, functions, interfaces	nil

Example

Declare variables without initialization and print their zero values.

Code example

package main

import "fmt"

func main() {
    var a bool
    var b int
    var c float64
    var d string
    var e []int
    var f map[string]int

    fmt.Printf("bool: %v\n", a)
    fmt.Printf("int: %v\n", b)
    fmt.Printf("float64: %v\n", c)
    fmt.Printf("string: %q\n", d)
    fmt.Printf("slice: %v\n", e)
    fmt.Printf("map: %v\n", f)
}

Output

bool: false
int: 0
float64: 0
string: ""
slice: []
map: map[]

Useful links

• Go specification: Zero value
• Go by Example: Zero Values