Chaining filter, map, and reduce
We can chain filter, map, and reduce. The following lines declare a new summedHighestScoresWhere method for our previously coded GameRepository class that chains filter, map, and reduce calls. The code file for the sample is included in the swift_3_oop_chapter_07_30 folder:
open func summedHighestScoresWhere(minPlayedCount: Int) -> Int {
return getAll().filter({ $0.playedCount >=
minPlayedCount }).map({ $0.highestScore }).reduce(0) {
sum, highestScore in
return sum + highestScore
}
}
The summedHighestScoresWhere method receives a minPlayedCount argument of the Int type and returns an Int value. The code calls the getAll and filter methods to generate a new Array<Game> with only the Game instances, whose playedCount value is greater than or equal to the value specified in the minPlayedCount argument. The code calls the map method to transform an Array<Game>...
