swift字典

//声明字典

//空字典
let dic = [:]

print(dic)
//限定键值类型的空字典 key为string类型 value
var dic1 = Dictionary()
var dic2:Dictionary = ["1":111,"2":222]
var dic3:[String:Int] = ["1":111]

print(dic1, dic2 ,dic3)

var newDic = ["key":"value","朕":"本帝"]
print(newDic)
//查询
var theValue = newDic["key"]
print(theValue)
//增加/修改
//查找字典,若原字典有这个key,则更改对应的value;若无,则添加一对新的键值对
newDic["key"] = "newValue"
print(newDic)
newDic["you"] = "zha5"
print(newDic)

newDic.updateValue("shui", forKey: "shen")
print(newDic)

//如果原字典没有这个key,会返回一个nil,并添加进去,如果存在,返回value
if let isnil = newDic.updateValue("nil", forKey:"buzai") {
print(isnil)
}else{
// print(isnil)
print("原来不存在")
}

print(newDic)

//删除

newDic["buzai"] = nil
print("删除了"buzai 后----(newDic)")

//如果key存在删除对应的键值对并返回key对应的值,不存在key返回nil字典不变
if let value = newDic.removeValueForKey("shen") {
print(value)
print("yes--(newDic)")

}else{
print("no--(newDic)")

}
//字典的元素个数
print(newDic.count)
print(String(newDic.count))

//遍历字典
for (key,value) in newDic{
print("(key):(value)")
}
//遍历所有的key
for key in newDic.keys{
print(key)
print(newDic[key])
}
//遍历所有的value
for value in newDic.values{
print(value)
}

let allKeys = Array(newDic.keys)
let allValue = newDic.values
print(allKeys)
print(allValue)