Swift3.0 - 字典

var namesOfIntegers = [Int: String]()
var airports: [String: String] = ["YYZ": "Toronto Pearson", "DUB": "Dublin"]
var airports = ["YYZ": "Toronto Pearson", "DUB": "Dublin"]

namesOfIntegers[16] = "sixteen"
airports["LHR"] = "London Heathrow"

 // 更新值返回久的值,值可能为nil
 if let oldValue = airports.updateValue("Dublin Airport", forKey: "DUB") {
print("The old value for DUB was \\(oldValue).")
}
if let x = dic[1]{
print(x)
}

namesOfIntegers = [:]

if airports.isEmpty {}

dic[1] = nil
dic.removeValue(forKey: 1)

for (airportCode, airportName) in airports {
    print("\\(airportCode): \\(airportName)")
}
for airportCode in airports.keys {
   print("Airport code: \\(airportCode)")
}
for airportName in airports.values {
   print("Airport name: \\(airportName)")
}

var dic = [1:"23",3:"3"]
dic.remove(at: dic.index(dic.startIndex, offsetBy: 1))
print(dic)

  let keys = [Int](dic.keys)
  let values = [String](dic.values)