从 Swift 中解码的 JSON 中提取字符串数组

Question

I am using JSONDecoder to decode JSON obtained from an API into an array of objects each of which contains a key value pair of interest. For that key, I would like to obtain an array of the values (that are strings). The JSON decodes fine into an array, however, I cannot extract an array of values for the key I'm interested in using Array[key]. What am I doing wrong?

Starting JSON looks like:

[{"word":"hi"},{"word":"howdy"},{"word":"hullo"}]

My code:

struct Synonym: Codable {
        let word: String
    }
typealias Synonyms = [Synonym]
//Code to create session etc and get data
let mysynonyms = try? JSONDecoder().decode(Synonyms.self, from: data) 

//everything works fine up to here
var words = mysynonyms?[word]! //THROWS ERROR Use of unresolved identifier 'word'

Would appreciate any suggestions into why the last line does not work.

Answer 1

var words = (mysynonyms?? []).map { $0.word }

Using the [] subscript syntax on a type (struct/class) doesn't work in Swift -- instead, you need to use the dot syntax to get the property. And, since you want all of the words, you can use map to transform the array.

I'm also using the ?? to say "if mysynonyms is nil, map an empty array instead" so words will be [] in the event that mysynonyms was nil .