Data commit

Task/Averages-Mode/Swift/averages-mode.swift

@@ -0,0 +1,27 @@
+// Extend the Collection protocol. Any type that conforms to extension where its Element type conforms to Hashable will automatically gain this method.
+extension Collection where Element: Hashable {
+
+    /// Return a Mode of the function, or nil if none exist.
+    func mode() -> Element? {
+        var frequencies = [Element: Int]()
+
+        // Standard for loop. Can also use the forEach(_:) or reduce(into:) methods on self.
+        for element in self {
+            frequencies[element] = (frequencies[element] ?? 0) + 1
+        }
+
+        // The max(by:) method used here to find one of the elements with the highest associated count.
+        if let ( mode, _ ) = frequencies.max(by: { $0.value < $1.value }) {
+            return mode
+        } else {
+            return nil
+        }
+    }
+
+}
+
+["q", "a", "a", "a", "a", "b", "b", "z", "c", "c", "c"].mode() // returns "a"
+[1, 1, 2, 3, 3, 3, 3, 4, 4, 4].mode() // returns 3
+
+let emptyArray: [Int] = []
+emptyArray.mode() // returns nil