Cannot Subscript a Value of Type '[String:String]' with an Index of Type 'String'

Cannot Subscript a value of type '[String]' with an index of type 'String'

In your first loop, you are doing

for x in pokemon

This casts each value in pokemon to x.

You don't need to subscript pokemon[x] as x is not an index, it is the element.

Naturally, you would get the error you got because:
- pokemon is an array of strings
- x is an element in pokemon (which makes it a string).

With this loop, this is happening in your code:

pokemon["snorlax"]

As arrays are subscriptable only by integer, this is invalid.

For this loop, one only needs to

name = x

to cast the value of the currently iterated element of pokemon to the variable.

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In your second loop, you're iterating through an integer sequence (range).

for x in 1..<pokemon.count

The range 1..<pokemon.count gives x the value of 1, 2, 3... and so on per iteration until you reach one less than the count of Pokemons in the array.

This works because you are now subscripting array pokemon to an integer value of x.

With this loop, this is happening in your code:

pokemon[1] // contains string "snorlax"`

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Also, I'm not sure if this is a mistake in your code but starting the range at 1 means that you'll exclude the first element of a zero-indexed array, in which the first element is 0.

Cannot subscript a value of type '[[String : Any]]' with an index of type 'String'

[[String:Any]] is an array. It can be only subscripted by Int index.

You have to iterate over the array for example:

if let reviews = place.details?["reviews"] as? [[String:Any]] {
    for review in reviews {
        if let authorName = review["author_name"] as? String {
           // do something with authorName
        }
    }
}

Why I Cannot subscript a value of type '[String : [String]]' with an argument of type 'String.SubSequence' (aka 'Substring')?

You can simply use Dictionary's init(grouping:by:) initializer like so,

var animalsDict = Dictionary(grouping: animals) { String($0.first!) }

var animalSectionTitles = animalsDict.keys.sorted()

Output:

print(animalsDict) //["G": ["Giraffe", "Greater Rhea"], "P": ["Panda", "Peacock", "Pig", "Platypus", "Polar Bear"], "E": ["Emu"], "H": ["Hippopotamus", "Horse"], "K": ["Koala"], "L": ["Lion", "Llama"], "R": ["Rhinoceros"], "D": ["Dog", "Donkey"], "B": ["Bear", "Black Swan", "Buffalo"], "M": ["Manatus", "Meerkat"], "W": ["Whale", "Whale Shark", "Wombat"], "S": ["Seagull"], "T": ["Tasmania Devil"], "C": ["Camel", "Cockatoo"]]

print(animalSectionTitles) //["B", "C", "D", "E", "G", "H", "K", "L", "M", "P", "R", "S", "T", "W"]

Cannot subscript a value of type '[String : String]' with an index of type 'Int'

In the below code,

var menuItems:[String:String] = ["image1":"Order", "image2":"Notifications", "image3":"Free orders", "image4":"Payment", "image5":"Help", "image6":"Settings"]

menuItems is a Dictionary. Since it is a dictionary, the items in it will be unordered. So, whenever you try to get an element from it based on indexPath, you might get different result each time.

Reason for error:

Also, since it is a Dictionary of type [String:String], you definitely cannot get the elements from it using an Int, i.e. indexPath.row as the subscript. That's the reason you're getting the error.

Solution:

Instead, you must create a separate type - class/struct to store a single menuItem.

struct MenuItem {
    let pageIcon: String
    let pageName: String
}

Now, the menuItems array will be of type [MenuItem],

var menuItems = [MenuItem]()
menuItems.append(MenuItem(pageIcon: "image1", pageName: "Order"))
menuItems.append(MenuItem(pageIcon: "image2", pageName: "Notifications"))
menuItems.append(MenuItem(pageIcon: "image3", pageName: "Free orders"))
menuItems.append(MenuItem(pageIcon: "image4", pageName: "Payment"))
menuItems.append(MenuItem(pageIcon: "image5", pageName: "Help"))
menuItems.append(MenuItem(pageIcon: "image6", pageName: "Settings"))

menuItems will contain the MenuItem objects containing the required data. Use menuItems as dataSource of tableView.

Now, in tableView(_: cellForRow:), you can get the menuItem like,

cell.pageIcon.image = UIImage(named: menuItems[indexPath.row].pageIcon)
cell.pageName.text = menuItems[indexPath.row].pageName

Cannot subscript a value of type '[String : String]?' with an index of type 'String'

The error is because you're trying to use the subscript on an optional value. You're casting to [String: String] but you're using the conditional form of the casting operator (as?). From the documentation:

This form of the operator will always return an optional value, and the value will be nil if the downcast was not possible. This enables you to check for a successful downcast.

Therefore orch is of type [String: String]?. To solve this you need to:

1. use as! if you know for certain the type returned is [String: String]:

// You should check to see if a value exists for `orch_array` first.
if let dict: AnyObject = NSUserDefaults().dictionaryForKey("orch_array")?[orchId] {
    // Then force downcast.
    let orch = dict as! [String: String]
    orch[appleId] // No error
}

2. Use optional binding to check if orch is nil:

if let orch = NSUserDefaults().dictionaryForKey("orch_array")?[orchId] as? [String: String] {
    orch[appleId] // No error
}

Hope that helps.

Cannot subscript a value of type '[String : Int]' with an index of type 'String?'

The error indicates, that MUser.sharedInstance.getUserId() returns an optional.

You need to unwrap this:

self.books = self.books.filter {  
  guard let userID = MUser.sharedInstance.getUserId() else { return false }
  return $0.completed[userID] ?? 0 > 0 
}

Swift 4: Cannot subscript a value of type 'String' with an index of type 'CountablePartialRangeFromInt'

Whoops. Seems I needed to just do this:

let idx = response.index(response.startIndex, offsetBy: 11)
let substr = response[idx...]

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