Check if Dictionary is inside Array of Dictionaries in Swift 3

Question

I have an array of dictionaries like this:

var suggestions = [["keyword": "apple", "identifier": "0"], ["keyword": "banana", "identifier": "1"], ["keyword": "carrot", "identifier": "2"]]

I would like to append the suggestions array and before I do that, I want to know if the dictionary already exists inside of my array to prevent duplicates. How can I do that in Swift 3?

I tried to use the contains(where: ([String: String)]) function for Swift 3 but I can't seem to make it work.

UPDATE: The answer by Daniel Hall made it work. Here's the exact code for Swift 3:

let newDictionary = ["keyword": "celery", "identifier": "3"]
if !suggestions.contains(where: {$0 == newDictionary}) {
    suggestions.append(newDictionary)
}

Answer 1

I think the solution is more straightforward than the other answers suggest. Just use:

let newDictionary = ["keyword":"celery", "identifier": "3"]
if !suggestions.contains{ $0 == newDictionary } {
    suggestions.append(newDictionary)
}

This makes sure that your existing array of dictionaries does not contain the new dictionary you want to add before appending it.

Answer 2

Instead of using dictionaries, you can create a struct representing your data types like.

internal struct Entry {
    let id: String
    let keyword: String
}

extension Entry: Equatable {
    static func == (lhs: Entry, rhs: Entry) -> Bool {
        return lhs.id == rhs.id && lhs.keyword == rhs.keyword
    }
}

let suggestions: [Entry] = [] //...
let newEntry = Entry(id: "3", keyword: "orange")


if suggestions.contains(newEntry) {
    // Do Something
} else {
    // Insert maybe?
}

If you prefer to just keep using dictionary, you can use contains

let newEntry = ["keyword": "orange", "identifier": "4"]
let containsEntry = suggestions.contains{ $0["identifier"] == newEntry["identifier"] }
if containsEntry {
    // Do something
} else {
    // Insert maybe?
}

I would go for the struct option .