Semi-prepped for Flatmap

Author: Bob Lee

source-code/.DS_Store

@@ -8,87 +8,31 @@
  ---
  */
 
-//: Test Driven Development
-// -Onone // none a.k.a. debug
-// -O // fast a.k.a. release
-// -Ounchecked // super fast testing
+ 
 
-/*:
+// Element Associated Type
+ let twoDArray = [1, 2, 3]
+ let threeDArray = [[1], [2], [3]]
 
- Standard Swift library come with five assertion functions
- 1. assert()
- 2. assertionFailure()
- 3. precondition()
- 4. preconditionFailure()
- 5. fatalError()
+ extension Array {
+ func typeCheckWithInt() {
+ if type(of: self) == [Int].self {
+ print("2D array")
+ }
+ if type(of: self) == [[Int]].self {
+ print("3D array")
+ }
+ }
 
- */
-//: assert()
-assert(true)
-
-
-func enterName(name: String) {
- if name == "" {
- assert(false, "You must enter a full name")
- } else if name == "Bob" {
- assert(false, "There is only one Bob")
- }
-}
-
-// enterName(name: "Bob")
-
-print("File: \(#file)")
-print("Line: \(#line)")
-
-
-
-var expectedResult = 10
-var actualResult = 10
-
-assert(actualResult == expectedResult, "The actual result doesn't match with the expected")
-
-
-//: assertionFailure()
-
-import Foundation
-let randomNumber: Int = Int(arc4random_uniform(3))
-
-
-switch randomNumber {
-case 0, 1, 2:
- print(randomNumber)
-default:
- assertionFailure("Unexpected index \(randomNumber)")
-}
-
-//: precondition()
-// Identical as assert()
-let expectedNumber = (1, 3)
-let actualNumber = (1, 3)
-
-precondition(actualNumber == expectedNumber, "\(actualNumber) is not the same as \(expectedNumber)")
-
-//: PreconditionFailture()
-// preconditionFailure("Good")
-
-
-//: fatalError()
-let number: Int = Int(arc4random_uniform(100))
-
-func enterNumberReturnString(index: Int) -> String {
- switch index {
- case 0, 1, 2:
- return "\(number)"
- default:
-// assertionFailure("Unexpected index \(number)")
-// abort()
- fatalError("Unepxpected index \(number)")
- }
-}
-
-//: > `@noreturn`, the compiler confirms that the marked function will not return. The application would terminate instead.
-
-
+ func typeCheckWithElement() {
+ if type(of: self) == [Element].self {
+ print("2D array")
+ }
+ if type(of: self) == Element.self {
+ print("3D array")
+ }
+ }
+ }
 
 
 

source-code/10000_advanced-swift/.DS_Store

@@ -1,2 +1,2 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='6.0' target-platform='ios' display-mode='rendered'/>
+<playground version='6.0' target-platform='ios' display-mode='raw'/>

source-code/10000_advanced-swift/10006_associated_type_constraints.playground/Pages/8001_nested_generics_recursive_enum.xcplaygroundpage/Contents.swift

@@ -10,10 +10,38 @@
  */
 
 
+let example = [[5,2,7],[4,8],[9,1,3]]
+let result = example.flatMap { $0 }
+print(result)
+
+let anotherExample: [Int?] = [1, 2, nil, 3, 4, 5, nil, nil]
+let AnotherRsult = anotherExample.flatMap { $0 }
+
+
+func myFlatMap(numbers: [Int]) {
+ 
+}
+
+
+func bobFlatMap(numbers: [[Int]], operation: (Int) -> Int) {
+ var result: [Int] = []
+ for array in numbers {
+ for item in array {
+ result.append(item)
+ }
+ }
+ print(result)
+}
+
+
+bobFlatMap(numbers: [[1, 2, 3], [4, 5], [6, 7, 8]], operation: { $0 })
+bobFlatMap(numbers: [[1, 2, 3, 4, 5]], operation: { $0 })
+
+
 
 
 extension Array {
- func flatMap<U>(transform: (Element) -> U?) -> [U] {
+ func myFlatMap<U>(transform: (Element) -> U?) -> [U] {
  var result = [U]()
  for item in map(transform) {
  if let nonOptional = item {
@@ -24,23 +52,12 @@ extension Array {
  }
 }
 
+let closure: (Int) -> Int? = { $0 }
 
 
-
-
-
-
-
-
-
-let collections = [[5,2,7],[4,8],[9,1,3]]
-let flat = collections.flatMap { $0 }
-print(flat)
-
-
-let onlyEvenSimpler = collections.flatMap { $0.filter { $0 % 2 == 0 } }
-
-
+let myResult = [[1], [2], [3], nil].myFlatMap { $0 }
+let flattenCollection = myResult.joined()
+let flattenArray = Array(flattenCollection)