Question

struct GroupStruct {
var groupName = " "
var groupAge= " "
var tests: [TestStruct] = []
}

struct TestStruct {
var desc= " "
var title= " "
}

当GroupStruct.tests [0] .desc =“abc”时，索引超出范围。为什么会这样？谢谢你的帮助。

Answer 1

您必须初始化GroupStruct。然后在其上添加一个新元素。

import Foundation

struct GroupStruct {
    var groupName = " "
    var groupAge = " "
    var tests: [TestStruct] = []
}

struct TestStruct {
    var desc = " "
    var title = " "
}

// Creates a new instance of GroupStruct
var groupStruct = GroupStruct()

// Appends a new instance of TestStruct (will be at index 0)
groupStruct.tests.append(TestStruct(desc: "abd", title: ""))

Answer 2

这样做：

var groupStruct = GroupStruct() // Declare groupStruct instance
var TestStructObj = TestStruct(desc: "abc", title: "abc") // Create TestStruct instance
groupStruct.tests.append(TestStructObj) // Append it to tests array

提示 - 以这种方式声明数组：

var tests = [TestStruct]()

初始化数组时索引超出范围（快速）

2 个答案: