我创建了一个struct，并希望将其保存为JSON文件.
struct Sentence {
var sentence = ""
var lang = ""
}
var s = Sentence()
s.sentence = "Hello world"
s.lang = "en"
print(s)
...which results in:
Sentence(sentence: "Hello world", lang: "en")
But how can I convert the struct object to something like:
{
"sentence": "Hello world",
"lang": "en"
}
Swift 4引入了Codable协议，它提供了一种非常方便的方式来编码和解码自定义 struct .
struct Sentence : Codable {
let sentence : String
let lang : String
}
let sentences = [Sentence(sentence: "Hello world", lang: "en"),
Sentence(sentence: "Hallo Welt", lang: "de")]
do {
let jsonData = try JSONEncoder().encode(sentences)
let jsonString = String(data: jsonData, encoding: .utf8)!
print(jsonString) // [{"sentence":"Hello world","lang":"en"},{"sentence":"Hallo Welt","lang":"de"}]
// and decode it back
let decodedSentences = try JSONDecoder().decode([Sentence].self, from: jsonData)
print(decodedSentences)
} catch { print(error) }