在Swift中检查NSArray是否包含NSDictionary键？

Question

I have array of NSDictionary and i want check particular NSDictionary "key" present in NSArray or not.

I tried

if let val = dict["key"] {
    if let x = val {
        println(x)
    } else {
        println("value is nil")
    }
} else {
    println("key is not present in dict")
}

and

let arrayOfKeys = dictionary.allKeys
if (arrayOfKeys.containsObject(yourKey)) {

}
else {
}

but this is for individual array object. Also

if ([[dictionary allKeys] containsObject:key]) {
    // contains key
}

This method for individual NSDictionary not for NSArray.

Also

if readArray.contains(["A":1]) {                  ALToastView.toastInView(UIApplication.sharedApplication().keyWindow, withText: "Already added")
      }else{
           readArray.append(["A":0]
       }

This code will add again same key in array if change value for key "A"

Ex. My array contain dictionary ["A":1] and i want to check key "A" is present or not? How do i check any key present in Array? Do i need to iterate array? Thanks in advance.

Answer 1

Refer following example :

var array = [[String:Any]]()

array.append(["key1":"value1"])
array.append(["key2":"value2"])
array.append(["key3":"value3"])
array.append(["key4":"value4"])
array.append(["key5":"value5"])

let key = "key5"

if let index = (array.indexOf { (dict) -> Bool in
    dict[key] != nil
})
{
    print("Key Found at = \(index) ")
} else {
    print("Key not Found")
}

Answer 2

You can use this method. Basically you iterate thru the array of dict getting a tuple of its index and dict and if the dict contains the key you store the index in an array.

let arrayOfDict = [
["key1":"value1", "key2":"value2"],
["key3":"value3", "key4":"value4", "key5":"value5"],
["key6":"value6", "key7":"value7", "key8":"value8"],
["key6":"value6", "key7":"value7", "key8":"value8"]
];

let keyToCheck = "key6"
var foundIndex = [Int]()
for (index, dict) in arrayOfDict.enumerate()
{
    if let item = dict[keyToCheck] {
            foundIndex.append(index)
    }
}
if foundIndex.count > 0 {
    print("Found at \(foundIndex)")
} else {
    print ("not found")
}

Answer 3

You can also use this method if you want to get the dictionaries that contains the keys along with the index.

let newArray = arrayOfDict.enumerate().filter { (tuple:(index: Int, element: Dictionary<String, String>)) -> Bool in
    if tuple.element.keys.contains(keyToCheck) {
        return true
    } else  {
        return false
    }
}

The newArray will be an array of tuples of type (Int:[String:String]) wherein the tuple.0 will be the index and tuple.1 will be the dictionary