Index out of range when initialise an array (swift)

Question

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

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

Index out of range when GroupStruct.tests[0].desc = "abc" . why did that happen? thanks for helping.

because its empty? have you initialize GroupStruct.tests? have you add any TestStruct? — seto nugroho
– seto nugroho, Commented Aug 11, 2016 at 8:06
GroupStruct.tests[0].groupName = "abc" - I see three mistakes in this line. Try to rethink what are you doing and what are you need to achieve — Yury
– Yury, Commented Aug 11, 2016 at 8:06

brduca · Accepted Answer · 2016-08-11 08:19:36Z

1

You must initialize the GroupStruct. Then add the a new element on it.

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: ""))

answered Aug 11, 2016 at 8:19

brduca

3,6332 gold badges25 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

ray ray Over a year ago

It seems it will start at index 1 instead of 0

brduca Over a year ago

Not really, the list is initialized but is empty, It will be added at index 0. Try print(groupStruct.tests[0]) and you'll see.

Roy K · Accepted Answer · 2016-08-11 08:33:46Z

0

Do it this way:

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

Tip - declare the array this way:

var tests = [TestStruct]()

edited Aug 11, 2016 at 8:33

answered Aug 11, 2016 at 8:18

Roy K

3,3292 gold badges29 silver badges44 bronze badges

1 Comment

brduca Over a year ago

It will not add on the GroupStruct array, only on the "tests" array.

Collectives™ on Stack Overflow

Index out of range when initialise an array (swift)

2 Answers 2

2 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related