如何使用swift中的Dictionary
本篇内容主要讲解“如何使用swift中的Dictionary”,感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷,实用性强。下面就让小编来带大家学习“如何使用swift中的Dictionary”吧!
定义
//定义 var dic1 = Dictionary<String, Int>() var dic2 = [String: Int]() var dic3: Dictionary<String, Int> = [:] var dic = ["zhang san": 18, "li si": 19, "wang wu": 20]
是否为空 & 元素数量
print(dic.isEmpty) //false print(dic.count) //3
遍历
//无序遍历字典 for (key, value) in dic { print("name: \(key), age:\(value)") } /* name: li si, age:19 name: wang wu, age:20 name: zhang san, age:18 */ //有序遍历 for key in dic.keys.sorted() { print("name: \(key), age:\(dic[key]!)") } /* name: li si, age:19 name: wang wu, age:20 name: zhang san, age:18 */
update
//update dic["zhang san"] = 19 print(dic) //["li si": 19, "wang wu": 20, "zhang san": 19] //updateValue dic.updateValue(20, forKey: "zhang san") print(dic) //["li si": 19, "wang wu": 20, "zhang san": 20]
remove
//remove dic["zhang san"] = nil print(dic) //["li si": 19, "wang wu": 20] //removeValue print(dic.removeValue(forKey: "li si")) //Optional(19) print(dic) //["wang wu": 20]
merge
//merge var mergeDic = ["a": 1, "b": 2] mergeDic.merge(["a": 3, "c": 4]) { (current, _) in current } print(mergeDic) //["c": 4, "a": 1, "b": 2] mergeDic.merge(["a": 3, "d": 6]) { (_, new) in new } print(mergeDic) //["b": 2, "c": 4, "a": 3, "d": 6]
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