從枚舉數組調用Array.reduce（_：_）

Question

正常的reduce電話：

[1,2,3].reduce(0, { cur, val in
  return val
})

嘗試從EnumeratedSequence<Array<Element>>調用reduce ：

    [1,2,3].enumerated().reduce(0, { cur, (index, element) in
      return element
    })
  // Error: consecutive statements on a line must be separated by ';'" (at initial reduce closure)

Answer 1

您可以訪問element與元組的val.element和index與val.offset ：

let result = [1,2,3].enumerated().reduce(0, { cur, val in
    return val.element
})

---

另外，您可以使用賦值來訪問元組中的值：

let result = [1,2,3].enumerated().reduce(0, { cur, val in
    let (index, element) = val
    return element
})