要将一个新的键-值对追加到字典中，您只需设置键的值。如。

// Initialize the Dictionary
var dict = ["name": "John", "surname": "Doe"]
 
// Add a new key with a value

dict["email"] = "john.doe@email.com"

print(dict)

输出——>“姓”:“母鹿”、“名称”:“约翰”,“电子邮件”:“john.doe.com”)

我知道这可能会很晚，但它可能会对某人有用。 因此，在swift中将键值对追加到字典中，你可以使用updateValue(value:， forKey:)方法，如下所示:

var dict = [ 1 : "abc", 2 : "cde"]
dict.updateValue("efg", forKey: 3)
print(dict)

如果你想修改或更新NSDictionary那么 首先，将它类型转换为NSMutableDictionary

let newdictionary = NSDictionary as NSMutableDictionary

然后简单地使用

 newdictionary.setValue(value: AnyObject?, forKey: String)

从Swift 5开始，以下代码收集工作。

 // main dict to start with
 var myDict : Dictionary = [ 1 : "abc", 2 : "cde"]

 // dict(s) to be added to main dict
 let myDictToMergeWith : Dictionary = [ 5 : "l m n"]
 let myDictUpdated : Dictionary = [ 5 : "lmn"]
 let myDictToBeMapped : Dictionary = [ 6 : "opq"]

 myDict[3]="fgh"
 myDict.updateValue("ijk", forKey: 4)

 myDict.merge(myDictToMergeWith){(current, _) in current}
 print(myDict)

 myDict.merge(myDictUpdated){(_, new) in new}
 print(myDict)

 myDictToBeMapped.map {
     myDict[$0.0] = $0.1
 }
 print(myDict)

var dict = ["name": "Samira", "surname": "Sami"]
// Add a new enter code herekey with a value
dict["email"] = "sample@email.com"
print(dict)

斯威夫特 3+

向Dictionary分配新值的示例。你需要声明它为NSMutableDictionary:

var myDictionary: NSMutableDictionary = [:]
let newValue = 1
myDictionary["newKey"] = newValue
print(myDictionary)