附加到[String：Any]字典结构中的数组

的类型

data[Items]

Array

Array<[String: Any]>

您可以将其压缩为更少的步骤，但是我更喜欢多步骤的清晰度：

var data: [String: Any] = [    "key1": "example value 1",    "key2": "example value 2",    "items": []]for index in 1...3 {    let item: [String: Any] = [        "key": "new value"    ]    // get existing items, or create new array if doesn't exist    var existingItems = data["items"] as? [[String: Any]] ?? [[String: Any]]()    // append the item    existingItems.append(item)    // replace back into `data`    data["items"] = existingItems}