The difference between arrays and slice as parameters in Golang

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For example, [5]int is an array, []int is a slice (array slice), the arrays are value types, and slice is a reference type, the value type is passed as a parameter to the function, only a copy is copied, the modification does not affect the passed parameter, so the general use of slice as a parameter, The consumption of the copy is eliminated, but there is a pit in it, below is an example to illustrate.

1.slice as a parameter

package mainimport "fmt"type DbItem struct {    Id  int16    Cnt int32}func combineItem(itemList []DbItem, id int16, cnt int32) {    item := DbItem{Id: int16(id), Cnt: int32(cnt)}    itemList[0] = item    fmt.Printf("combineItem itemList values: %v \n", itemList)}func main() {    itemList := make([]DbItem, 5)    combineItem(itemList, int16(1), int32(2))    fmt.Printf("main itemList values: %v \n", itemList)}

The results of the operation are as follows:
Combineitem itemList values: [{1 2} {0 0} {0 0} {0 0} {0 0}]
Main ItemList values: [{1 2} {0 0} {0 0} {0 0} {0 0}]

2. Array as a parameter.

package mainimport "fmt"type DbItem struct {    Id  int16    Cnt int32}func combineItem(itemList [5]DbItem, id int16, cnt int32) {    item := DbItem{Id: int16(id), Cnt: int32(cnt)}    itemList[1] = item    fmt.Printf("combineItem itemList values: %v \n", itemList)}func main() {    itemList := [5]DbItem{{Id: 3, Cnt: 4}}    combineItem(itemList, int16(1), int32(2))    fmt.Printf("main itemList values: %v \n", itemList)}

The results of the operation are as follows:
Combineitem itemList values: [{3 4} {1 2} {0 0} {0 0} {0 0}]
Main ItemList values: [{3 4} {0 0} {0 0} {0 0} {0 0}]

3. In particular, it is important to note that if append is used within a function, you should never use parameters as references.

 package main        import "fmt"        type DbItem struct {        Id  int16        Cnt int32    }        func combineItem(itemList []DbItem, id int16, cnt int32) {        item := DbItem{Id: int16(id), Cnt: int32(cnt)}        itemList = append(itemList, item)        fmt.Printf("combineItem itemList values: %v \n", itemList)    }        func main() {        itemList := make([]DbItem, 5)        combineItem(itemList, int16(1), int32(2))        fmt.Printf("main itemList values: %v \n", itemList)    }

The results of the operation are as follows:
Combineitem itemList values: [{0 0} {0 0} {0 0} {0 0} {0 0} {1 2}]
Main ItemList values: [{0 0} {0 0} {0 0} {0 0} {0 0}]

For specific reasons see: Https://segmentfault.com/a/11 ...