How does golang assign values to empty structures

One 、 Preface

       I haven't used less recently golang, I haven't learned systematically , Directly go up and develop , Encounter many pits and learn a lot , This time, the problem of assigning values to empty structures is recorded .

Two 、 Case study

1. Structure structure and error

type Test struct {
    Test1     int64  `gorm:"column:test1" json:"test1"`
    Test2     string `gorm:"column:test2" json:"test2"
}

var test []*Test
    // This way is a failure ?  Because it is empty at present , Can't use something like php The way to write dead 
    test[0].Test1 = xxx
    test[0].Test2 = xxxx

       Here you can see , I wanted to fill it directly , But life or death cannot be written , Habitual thinking kills people , Online Baidu reason It's an empty structure , Pointer for nil, It doesn't take up memory space , Cannot assign

2. How to assign values to empty structures

（1） The first method

 Direct assignment  （ It means that this is a testStruct{} type ）
         
          test1 :=testStruct{
            Test1:          xx,
            Test2:          xx,
        }

（2） The second method

 test1 := &testStruct{}
 test1.Test1 = int64(0)

（3） The third method

  test1 :=new(testStruct)
  test1.Test1 = int64(0)

（4） About new and make The difference between initialization

new：  Suitable for creating pointers , Generally, create basic types ,int etc. , The return is the pointer 
make： Mainly create reference types , Like slicing ,map. What is returned is the reference of the created type itself , Modification will affect itself , Be similar to php Of &
    make Be similar to []int{}  To initialize the .

       Tell the truth , A little cumbersome , In fact, the key is to initialize this structure , Just quote , This does not return nil, The rest is naturally easy to operate ..

end