已有：
if extraParas is Dictionary<String, AnyObject> { |
现在要去判断这个dict中是否已经存在某个 key，比如：
httpVerb
但是对于：
if let httpVerbStr = extraParas!["httpVerb"] { |
结果已经是nil，却还是可以继续执行。。。
所以想要去搞清楚：
如何判断
Dictionary<String, AnyObject>
中是否存在某个key
试着找了下，没找到。
包括
isExisted
containKey之类的
但是都没找到。
swift dictionary has key
Determining if Swift dictionary contains key and obtaining any of its values – Stack Overflow
改为：
if let httpVerbStr = extraParas?["httpVerb"]
也不行。
swift dictionary contain key
if extraParas!.containsValueForKey("httpVerb") { |
出错：
2015-12-10 14:47:27.940 JianDao[6710:263838] *** Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘-[_TtGCSs29_NativeDictionaryStorageOwnerSSSS_ containsValueForKey:]: unrecognized selector sent to instance 0x7f9243e0b170’ |
swift dictionary contains key
swift dictionary check contains key
swift check contain key for dict
swift dict contains
Swift Dictionary: String and Int Lookups, Contains Keys
Traversing an array that contains dictionaries in Swift | Treehouse Community
The Swift Swift Tutorial: How to Use Dictionaries in Swift | Making App Pie
最后，确定：
应该还是编译器的bug，导致了，无法检测到对应的值：
//if let httpVerbStr = extraParas?["httpVerb"] { if let httpVerbStr = extraParas!["httpVerb"] { //if extraParas!["httpVerb"] != nil { // if extraParas!.containsValueForKey("httpVerb") { // let arrayOfKeys = extraParas!.allKeys // if arrayOfKeys.contains("httpVerb") { // let httpVerbStr = extraParas!["httpVerb"] // print("httpVerbStr=\(httpVerbStr)") //nil // if httpVerbStr != nil { //// let httpVerbStr = extraParas!["httpVerb"] httpVerb = httpVerbStr as? String print("httpVerb=\(httpVerb)") //POST } |
从
extraParas!["httpVerb"]
得到的httpVerbStr
虽然是nil，但是代码仍会执行。。
print("httpVerbStr=(httpVerbStr)") //nil
if httpVerbStr != nil {
－》所以只能说明是编译器有问题。。。
算了，懒得理会了。。。
【总结】
最后还是变成之前的代码：
if let httpVerbStr = extraParas!["httpVerb"] { httpVerb = httpVerbStr as? String print("httpVerb=\(httpVerb)") //POST } |
即可。