[Swift]配列をループで条件を探すいろんな書き方

基本的な書き方

let saveValue: Int = 1
Private fund checkSaveValue (array: [Int]) -> Bool {
    for value in array {
        if value == saveValue {
            return true
        }
    }
    return false
}

.filterを使う

let saveValue: Int = 1

private func checkSaveValue(array: [Int]) -> Bool {
    array.filter { value in
        value == saveValue
    }.first != nil
}

.Containsを使う

let saveValue: Int = 1

private func checkSaveValue(array: [Int]) -> Bool {
    return array.contains { $0 == self.saveValue }
}

.enumerate()を使う

let array = [1, 2, 3, 4]

let pairList = array.enumerate().map { (tuple: (count: Int, int: Int)) -> String in
    return count == int
}

いろいろ合わせた例

これ↓を

var checkedIndexPath: [NSIndexPath] = []
private func checkeIndex(indexPath: NSIndexPath) -> Int? {
   var returnIndex: Int? = nil
   checkedIndexPath.enumerate().forEach { (index, data) in
      if data == indexPath {
          returnIndex = index
      }
    }
  return returnIndex
}

いろいろ合わせてこう書ける↓

var checkedIndexPath: [NSIndexPath] = []
private func checkedCellIndex(indexPath: NSIndexPath) -> Int? {
    return checkedIndexPath
        .enumerate()
        .filter { $0.1 == indexPath }
        .flatMap { return $0.0 }
        .first
}