字典在我们日常的开发中是不可或缺的集合类型,它是无序的、键值对集合。下面图片列出字典的常用方法和相关使用:
接下来我们以代码的角度来了解学习一下字典:
首先是初始化字典:
var dict = ["name":"jiege","age":"24","sex":"male"]
//初始化空字典
var dic1:Dictionary<String,String> = [:]
var dic2:[String:String] = [:]
var dic3 = [String:String]()
var dict4 = Dictionary<String,String>()
//有则更新键值对的值,没有的增加一个键值对
dic["hometown"] = "zhengzhou"
//updateValue:有则更新键值对的值,没有则增加一个键值对,返回oldValue
dict.updateValue("要飞的杰哥",forKey:"头条号")
dict.updateValue("25",forKey:"age")
print(dict)
//输出:["age":"25","sex":"male","hometown":"zhengzhou","头条号":"要飞的杰哥"]
//删除指定的键值对,没有这个键值对相当于无操作
dic.removeValueForKey("sex")
//删除所有的键值对
dict。removeAll()
//字典里键的集合
print(Array(dict.keys))
//输出
["age","name","sex","hometown","头条号"]
//字典里值的集合
print(Array(dict.values))
//输出
["25","jiege","male","zhengzhou","要飞的杰哥"]
//遍历字典的键(for..in)
for key in dict.keys{
print(key)
}
//遍历字典的值
for value in dict.values{
print(value)
}
//还可以遍历字典里元素的键值
for (key,value) in dict {
print("\(key):\(value)")
}
以上是Swift语言中字典的基本用法,大家可以参考学习。请大家多多关注点赞,谢谢!