Introduction to the difference between = and := in GO language

= is assignment, := is declaration of variables and assignment.

// = 使用必须使用先var声明例如：
var a
a=100
//或
var b = 100
//或
var c int = 100
// := 是声明并赋值，并且系统自动推断类型，不需要var关键字

Variable declaration

The first method is to specify the variable type. If it is not initialized, the variable defaults to zero value.

var v_name v_type
v_name = value

The second type is to determine the variable type based on the value.

var v_name = value

The third option is to omit var. Note: = If no new variable is declared on the left side, a compilation error will occur. Format:

v_name := value

Multiple variable declaration

//类型相同多个变量, 非全局变量
var vname1, vname2, vname3 type
vname1, vname2, vname3 = v1, v2, v3
var vname1, vname2, vname3 = v1, v2, v3 
// 和 python 很像,不需要显示声明类型，自动推断
vname1, vname2, vname3 := v1, v2, v3 
// 出现在 := 左侧的变量不应该是已经被声明过的，否则会导致编译错误
// 这种因式分解关键字的写法一般用于声明全局变量
var (
    vname1 v_type1
    vname2 v_type2
)

For more related knowledge, please pay attention to the go language tutorial column

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