变量(Variables)

变量(Variables)

在Go中，变量需要显式声明，并由编译器用于检查函数调用的类型正确性。

In Go, variables are explicitly declared and used by the compiler to e.g. check type-correctness of function calls.

var关键字用于声明一个或多个变量。

var declares 1 or more variables.

package main

import "fmt"

func main() {
	var a = "initial" 
	fmt.Println(a)    
}

package main

import "fmt"

func main() {
	var a = "initial" 
	fmt.Println(a)    
}

你可以一次声明多个变量。

You can declare multiple variables at once.

package main

import "fmt"

func main() {
	var b, c int = 1, 2 
	fmt.Println(b, c)
}

package main

import "fmt"

func main() {
	var b, c int = 1, 2 
	fmt.Println(b, c)
}

Go会根据初始化值推断变量的类型。

Go will infer the type of initialized variables.

package main

import "fmt"

func main() {
	var d = true 
	fmt.Println(d)
}

package main

import "fmt"

func main() {
	var d = true 
	fmt.Println(d)
}

没有对应初始化值的变量将被赋予零值。例如，int类型的零值为0。

Variables declared without a corresponding initialization are zero-valued. For example, the zero value for an int is 0.

package main

import "fmt"

func main() {
	var e int 
	fmt.Println(e)
}

package main

import "fmt"

func main() {
	var e int 
	fmt.Println(e)
}

:=语法是声明并初始化变量的简写形式，例如在此例中的 var f string = "apple"。此语法只能在函数内部使用。

The := syntax is shorthand for declaring and initializing a variable, e.g. for var f string = "apple" in this case. This syntax is only available inside functions.

package main

import "fmt"

func main() {
	f := "apple" 
	fmt.Println(f)
}

package main

import "fmt"

func main() {
	f := "apple" 
	fmt.Println(f)
}

运行

bash

go run 03-values.go
# golang
# 1+1 = 2
# 7.3/3.0 = 2.433333333333333
# false
# true
# false

go run 03-values.go
# golang
# 1+1 = 2
# 7.3/3.0 = 2.433333333333333
# false
# true
# false

运行 ​

运行