cannot subscript a value of type '[item]' with an index of type 'item'

I'm trying to loop trough an array within a JSON struct, but whatever I do i'm getting the error "Cannot subscript a value of type '[item]' with an index of type 'item'. I can print it whenever I call upon each index separately:

self.socialTitle = (storeSocialContext.items?[1].metatags?.first?.title)!
print(self.socialTitle)


Which gives me back a string, how i want it. But I want the strings of each index, for the title.
This is the loop which gives the error:

var anArray = storeSocialContext.items!

for socialIndex in anArray {
if anArray[socialIndex] != nil {

}

}


And this is the struct:

struct StoreSocialContext: Decodable
{
var items: [Item]?
}

struct Item: Decodable
{
var metatags: [enclosedTags]?

enum CodingKeys : String, CodingKey
{
case pagemap
}

enum PageMapKeys: String, CodingKey
{
case metatags
}

init(from decoder: Decoder) throws
{
let values = try decoder.container(keyedBy: CodingKeys.self)
let pagemap = try values.nestedContainer(keyedBy: PageMapKeys.self, forKey: .pagemap)
metatags = try pagemap.decode([enclosedTags].self, forKey: .metatags)
}
}

struct enclosedTags: Decodable
{
let image: String?
let title: String?
let description: String?
let siteName: String?

private enum CodingKeys : String, CodingKey
{
case image = "og:image", title = "og:title", description = "og:description", siteName = "og:site_name"
}
}


And this is a snipped of the data whenever I fetch and print the JSONdata in the console:

Optional([GetContext.Item(metatags: Optional([GetContext.enclosedTags(image:
nil, title: nil, description: nil, siteName: nil)])), GetContext.Item(metatags:
Optional([GetContext.enclosedTags(image: Optional("https://www.merriam-
webster.com/assets/mw/static/social-media-share/mw-logo-245x245@1x.png"),
title: Optional("Definition of BEST"), description: Optional("excelling all
others; most productive of good : offering or producing the greatest advantage,
utility, or satisfaction; most, largest… See the full definition"), siteName:
nil)])), ...])


What is socialTry? Why is your array of Item assigned to a variable named socialItem instead of socialItems? In your for loop, why is a single Item assigned to a variable named socialIndex? Better variable naming will make your code much easier to read and it will make your issues easier to solve.
– rmaddy
2 days ago

socialTry

Item

socialItem

socialItems

for

Item

socialIndex

Tnx, I edited it. I messed up the variables while typing up the question. Hope it's more clear now. Let me know if not.
– PR10
2 days ago

A for-in loop iterates over the items in the array, not the index. So unless you need the index itself for something, you already have your item and don't need to subscript anything. See docs.swift.org/swift-book/LanguageGuide/ControlFlow.html
– John Montgomery
2 days ago

Apart from the issue the nil check is pointless. The array doesn't contain any optionals.
– vadian
2 days ago

nil

1 Answer
1

This part:

for socialIndex in anArray {
if anArray[socialIndex] != nil {
//do stuff
}
}


Doesn't make any sense.

If you have a type Thing, and an array

Thing

var array: [Thing] = [thing1, thing2, thing3]


and you use the code for thing in array { //your code here }

for thing in array { //your code here }

then the variable thing contains elements of your array, and is of the type Thing

thing

Thing

In your code for socialIndex in anArray your variable socialIndex will contain elements from your array, and be of the type of those array elements.

for socialIndex in anArray

socialIndex

Thus the bit where you try to index into anArray: anArray[socialIndex] is not valid.

anArray[socialIndex]

You need to index into the array using Int indexes, and you've already extracted an element from the array, so there's no point.

This code:

let strings: [String?] = ["now", "is", "the", nil, "time"]

for string in strings {
if let aString = string {
print(aString)
}
}


Will output

now
is
the
time

now
is
the
time

And the code:

for string in strings {
if strings[string] != nil { //This makes no sense. `string` is of type String
}
}


Doesn't make sense.

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