Golang：if语句中的变量范围

问题描述

我最终对如何解决这个事实感到困惑，因为我可以' t在if语句中创建一个变量并在之后使用它。

这是我的代码。问题是new1不能在if语句之前创建，因为它的大小取决于if语句的结果，并且通过在if语句中创建它，我不能在if语句结束后使用它。

  
您可以声明 new1 在 if 块之前，并在内部使用 make ：
  var new1 []字符串
 $ b $如果len（array1）> len（array2）{
 new1 = make （[] string，0，len（array1））
 //指令... 
} else {
 new1 = make（[] string，0，len（array2））
 //其他指令... 
} 
 
 new2：= make（[] string，0，len（new1））
 copy（new2，new1）
  
 
I've just started learning Go today and have got stuck on variable scopes.
I've ultimately confused about how to get around the fact that I can't create a variable inside an if statement and the use it afterward.
This is my code. The problem is that new1 can't be created before the if statement because its size is dependent upon the result of the if statement, and by creating it inside the if statement I can't use it after the if statement ends.
if len(array1)>len(array2) {
    new1 := make([]string,0,len(array1))
    mc := Array2Map_string(array1)
    for _,tok :=range array2 {
        _, ok := mc[tok]
        if ok {
            new1[len(new1)]=tok
            }
        }
    } else {
    new1 := make([]string,0,len(array2))
    mc := Array2Map_string(array2)
    for _,tok :=range array1 {
        _, ok := mc[tok]
        if ok {
            new1[len(new1)]=tok
            }
        }
    }
new2 := make([]string,0,len(new1))
copy(new2, new1)
The only thing I can think of is to do something like
var pointlessvariable uint
if len(array1)>len(array2) {
pointlessvariable=len(array1)
} else {
pointlessvariable=len(array2)
}
var new1 = make([]string,0,pointlessvariable)
if len(array1)>len(array2) {
...
To be quite honest if that is truly the solution then I don't think I want to use Golang after all.
So what is the best way of solving this?
 解决方案 
You can declare new1 before the if block and use make inside:
var new1 []string

if len(array1)>len(array2) {
    new1 = make([]string, 0, len(array1))
    // instructions ...
} else {
    new1 = make([]string, 0, len(array2))
    // other instructions ...
}

new2 := make([]string, 0, len(new1))
copy(new2, new1)
                        
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