We can use our new repository to restrict the results retrieved from more complex data. In this case, the getAll method returns an array of Game instances, which we can use with the filter method to retrieve only the games that match certain conditions. The following lines declare a new getWithHighestScoreGreaterThan method for our previously coded GameRepository class. The code file for the sample is included in the swift_3_oop_chapter_07_13 folder:

    open func getWithHighestScoreGreaterThan(score: Int) -> [Game] { 
        return getAll().filter({ (game) in game.highestScore > score }) 
    } 

The getWithHighestScoreGreaterThan method receives a score: Int argument and returns Array<Game>, specified with the [Game] shortcut. The code calls the getAll and filter methods for the result with a closure that specifies the required condition for the games in the array to be returned in the new array. In this case, only the games whose highestScore value is greater than the score value received as an argument will appear in the resulting Array<Game>.

The following lines use the GameRepository instance called gameRepository to call the previously added method and then chain a call to forEach to print all the games whose highestScore value is greater than 5,000,000. The code file for the sample is included in the swift_3_oop_chapter_07_13 folder:

    gameRepository.getWithHighestScoreGreaterThan
    (score: 5_000_000).forEach( { print($0) }) 

The following lines show the output generated using the preceding code:

id: 3, name: "Minecraft Story Mode", highestScore: 67881050, 
    playedCount: 304506506

id: 7, name: "Cars Forever", highestScore: 6705203, playedCount: 850021

id: 10, name: "Mario Kart 2017", highestScore: 10572340, 
    playedCount: 3760879

The following code shows another version of the getWithHighestScoreGreaterThan method, which is equivalent and produces the same results. The code file for the sample is included in the swift_3_oop_chapter_07_14 folder:

    open func getWithHighestScoreGreaterThan(score: Int) -> [Game] {        
      return getAll().filter({ 
        (game: Game) -> Bool in 
        game.highestScore > score 
}) 
    } 

The following code shows another version of the getWithHighestScoreGreaterThan method, which is equivalent and produces the same results. The code file for the sample is included in the swift_3_oop_chapter_07_15 folder:

    open func getWithHighestScoreGreaterThan(score: Int) -> [Game] { 
      return getAll().filter({ $0.highestScore > score }) 
    }

The following lines declare a new getWith method for our previously coded GameRepository class. The code file for the sample is included in the swift_3_oop_chapter_07_16 folder:

    open func getWith(prefix: String) -> [Game] { 
      return getAll().filter({ game in game.name.hasPrefix(prefix) }) 
    } 

The getWith method receives a prefix, String argument and returns an Array<Game>, specified with the [Game] shortcut. The code calls the getAll method and calls the filter method for the result with a closure that specifies the required condition for the games in the array to be returned in the new array. In this case, only the games whose name includes the string specified in the prefix value and is received as an argument or prefix will appear in the resulting Array<Game>.

The following line uses the GameRepository instance called gameRepository to call the previously added method and then chains a call to forEach to print all the games whose name starts with "Mi". The code file for the sample is included in the swift_3_oop_chapter_07_16 folder:

    gameRepository.getWith(prefix: "Mi").forEach( { print($0) }) 

The following lines show the output generated by the preceding code:

id: 2, name: "Minecraft", highestScore: 3741050, playedCount: 780009992
id: 3, name: "Minecraft Story Mode", highestScore: 67881050, 
    playedCount: 304506506

The following code shows another version of the getWith method, which is equivalent and produces the same results. The code file for the sample is included in the swift_3_oop_chapter_07_17 folder:

    open func getWith(prefix: String) -> [Game] {
      return getAll().filter({ 
        (game: Game) -> Bool in 
        game.name.hasPrefix(prefix)        
      }) 
    }  

The following code shows another version of the getWith method, which is equivalent and produces the same results. The code file for the sample is included in the swift_3_oop_chapter_07_18 folder:

    open func getWith(prefix: String) -> [Game] { 
      return getAll().filter({ $0.name.hasPrefix(prefix) }) 
    }

So far, we have used the filter method to generate a new Array<Game>. Sometimes, we just want to retrieve a single element from an Array or a similar collection, and we also want to specify a more complex condition. The following lines declare a new getBy method for our previously coded GameRepository class. The code file for the sample is included in the swift_3_oop_chapter_07_18 folder:

    open func getBy(highestScore: Int, playedCount: Int) -> Game? { 
      return getAll().filter({ game in game.highestScore == 
      highestScore && game.playedCount == playedCount }).first 
    } 

The getBy method receives two Int arguments: highestScore and playedCount. The method returns an optional Game, that is, Game?. The code calls the getAll and filter methods for the result with a closure that specifies the required condition for the games in the array to be returned in the new array. In this case, only the games whose highestScore and playedCount values are equal to the values received as arguments with the same names will appear in the Array<Game> generated by the call to the filter method. Then, the call to the first method returns the first element in the generated array or nil if no elements are found.

The following lines use the GameRepository instance called gameRepository to call the previously added method to retrieve two games that match the specified highestScore and playedCount values. The method returns a  Game?; therefore, the code checks whether the result is a Game instance or not in each call using if statements. The code file for the sample is included in the swift_3_oop_chapter_07_18 folder:

    if let game0 = gameRepository.getBy(highestScore: 4023134, 
    playedCount: 350230) { 
      print(game0) 
    } else { 
      print("No game found with the specified criteria") 
    } 
    if let game1 = gameRepository.getBy(highestScore: 30, 
    playedCount: 40) { 
      print(game1) 
    } else { 
      print("No game found with the specified criteria") 
    }

The following lines show the output generated with the preceding code. In the first call, there was a game that matched the search criteria. In the second call, there is no Game instance included in the array that matches the search criteria:

id: 8, name: "Jake & Peter Pan", highestScore: 4023134, 
    playedCount: 350230
No game found with the specified criteria

The following code shows another version of the getBy method, which is equivalent and produces the same results. The code file for the sample is included in the swift_3_oop_chapter_07_19 folder:

    open func getBy(highestScore: Int, playedCount: Int) -> Game? { 
      return getAll().filter({ 
        (game: Game) -> Bool in 
        game.highestScore == highestScore && game.playedCount == 
        playedCount 
      }).first 
    } 

The following code shows another version of the getBy method, which is equivalent and produces the same results. The code file for the sample is included in the swift_3_oop_chapter_07_20 folder:

    open func getBy(highestScore: Int, playedCount: Int) -> Game? { 
      return getAll().filter({ $0.highestScore == highestScore && 
      $0.playedCount == playedCount }).first 
    }