Swift 3: Array to Dictionary?

Is that it (in Swift 4)?

let dict = Dictionary(uniqueKeysWithValues: array.map{ ($0.key, $0) })

Note:
As mentioned in the comment, using uniqueKeysWithValues would give a fatal error (Fatal error: Duplicate values for key: 'your_key':) if you have duplicated keys.

If you fear that may be your case, then you can use init(_:uniquingKeysWith:) e.g.

let pairsWithDuplicateKeys = [("a", 1), ("b", 2), ("a", 3), ("b", 4)] // or `let pairsWithDuplicateKeys = array.map{ ($0.key, $0) }`

let firstValues = Dictionary(pairsWithDuplicateKeys, uniquingKeysWith: { (first, _) in first })

print(firstValues)

//prints ["a": 1, "b": 2]

let lastValues = Dictionary(pairsWithDuplicateKeys, uniquingKeysWith: { (_, last) in last })

print(lastValues)

//prints ["a": 3, "b": 4]