Dictionary contains a certain value swift 3 - dictionary

Question

I want to check if a string exists in any of the values in my Dictionary
Dictionary<String, AnyObject>
I know arrays has .contains so I would think a dictionary does too. Xcode tells me to use the following when I start typing contains
countDic.contains(where: { ((key: String, value: AnyObject)) -> Bool in
<#code#>
})
I just don't understand how to use this I know inside I need to return a Bool, but I don't understand where I put what String I'm looking for. Any help would be great.

Answer 1

contains(where:) checks if any element of the collection satisfies
the given predicate, so in your case it would be
let b = countDic.contains { (key, value) -> Bool in
value as? String == givenString
}
or, directly applied to the values view of the dictionary:
let b = countDic.values.contains { (value) -> Bool in
value as? String == givenString
}
In both cases it is necessary to (optionally) cast the AnyObject
to a String in order to compare it with the given string.
It would be slightly easier with a dictionary of type
Dictionary<String, String> because strings are Equatable,
and the contains(element:) method can be used:
let b = countDic.values.contains(givenString)

Answer 2

Since your values are AnyObject – Any in Swift 3 - you have to check if the value is a string. If yes check if the value contains the substring.
let countDic : [String:Any] = ["alpha" : 1, "beta" : "foo", "gamma" : "bar"]
countDic.contains { (key, value) -> Bool in
if let string = value as? String { return string.contains("oo") }
return false
}
However if you want to check if any of the values is equal to (rather than contains) a string you could use also the filter function and isEmpty
!countDic.filter { (key, value) -> Bool in
value as? String == "foo"
}.isEmpty

Answer 3

You may need to learn basic usage of contains(where:) for Dictionarys first:
For [String: Int]:
let myIntDict1: [String: Int] = [
"a" : 1,
"b" : 101,
"c" : 2
]
let myIntDict1ContainsIntGreaterThan100 = myIntDict1.contains {
key, value in //<- `value` is inferred as `Int`
value > 100 //<- true when value > 100, false otherwise
}
print(myIntDict1ContainsIntGreaterThan100) //->true
For [String: String]:
let myStringDict1: [String: String] = [
"a" : "abc",
"b" : "def",
"c" : "ghi"
]
let myStringDict1ContainsWordIncludingLowercaseE = myStringDict1.contains {
key, value in //<- `value` is inferred as `String`
value.contains("e") //<- true when value contains "e", false otherwise
}
print(myStringDict1ContainsWordIncludingLowercaseE) //->true
So, with [String: AnyObject]:
let myAnyObjectDict1: [String: AnyObject] = [
"a" : "abc" as NSString,
"b" : 101 as NSNumber,
"c" : "ghi" as NSString
]
let myAnyObjectDict1ContainsWordIncludingLowercaseE = myAnyObjectDict1.contains {
key, value in //<- `value` is inferred as `AnyObject`
//`AnyObject` may not have the `contains(_:)` method, so you need to check with `if-let-as?`
if let stringValue = value as? String {
return value.contains("e") //<- true when value is a String and contains "e"
} else {
return false //<- false otherwise
}
}
print(myAnyObjectDict1ContainsWordIncludingLowercaseE) //->false
So, in your case:
let countDic: [String: AnyObject] = [
"a" : 1 as NSNumber,
"b" : "no" as NSString,
"c" : 2 as NSNumber
]
let countDicContainsString = countDic.contains {
key, value in //<- `value` is inferred as `AnyObject`
value is String //<- true when value is a String, false otherwise
}
print(countDicContainsString) //->true