从枚举数组调用 Array.reduce(_:_)

Question

正常reduce通话：

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

reduce尝试从以下位置调用EnumeratedSequence<Array<Element>>：

    [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

您可以使用和with访问element元组的：val.elementindexval.offset

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

或者，您可以使用赋值来访问元组中的值：

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