Append elements to a struct slice

php Xiaobian Youzi is here to introduce you to a cool technique - attaching elements to structure slices. Struct slice is a data structure used in Golang. It can store different types of elements and has the ability to dynamically expand. By appending elements to struct slices, we can easily extend and manipulate data collections, enabling more flexible and efficient programming. Let's take a look at how to use this technique to improve our programming skills!

Question content

I'm trying to append an element to a slice of a struct, but it returns the error invalidappend, which means that I passed The first parameter is not a slice.

Link to go playground.

code show as below:

type Item struct {
  Attr string
}

type ItemsList []Item

type IItemsList interface {
  GetItemsList() ItemsList
  AddItem(Item)
}

func NewItemsList() IItemsList {
  return &ItemsList{}
}

func (il *ItemsList) GetItemsList() ItemsList {
  return *il
}

func (il *ItemsList) AddItem(i Item) {
  il = append(il, i)
}

I don't know the correct way how to do this append operation.

Solution

The first parameter I passed is not a slice

The first parameter is a pointer to the slice.

type itemslist []item

func (il *itemslist) additem(i item) {
  il = append(il, i)
}

The first parameter is a slice.

func (il *ItemsList) AddItem(i Item) {
    *il = append(*il, i)
}

https://www.php.cn/link/97fc9b260a90d9c0aca468d2e6536980

go Programming Language Specification

Address Operator

For the operand x of pointer type *t, pointer indirect addressing *x represents the variable of type t pointed to by x.

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