Question

我只是想知道是否有任何方法可以提高我的循环速度，或建议最佳练习，因为我觉得它看起来很糟糕。

以下是代码：

for (index, _) in filteredArray.enumerate() {
    if index == 0 || index % 4 == 0 {
        let mediaItem = Item()
        mediaItem.id = filteredArray[index + 3]
        let photoURL = NSURL(string: filteredArray[index + 1])
        guard let url = photoURL else {  return  }
        let data = NSData(contentsOfURL: url)
        let finishImage = UIImage(data: data!)
        mediaItem.Photo = finishImage
        mediaItem.orderCount = filteredArray[index + 2]
        mediaItem.UUId = filteredArray[index]
        self.dataSourceItems.insert(mediaItem)
    }
}

Answer 1

尝试使用dispatch_apply。这样的事情：

let iterationsCount = filteredArray.count / 4
let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

dispatch_apply(iterationsCount, queue) { i in
    let index = i * 4
    let mediaItem = Item()
    mediaItem.id = filteredArray[index + 3]
    let photoURL = NSURL(string: filteredArray[index + 1])
    guard let url = photoURL else {  return  }
    let data = NSData(contentsOfURL: url)
    let finishImage = UIImage(data: data!)
    mediaItem.Photo = finishImage
    mediaItem.orderCount = filteredArray[index + 2]
    mediaItem.UUId = filteredArray[index]
    self.dataSourceItems.insert(mediaItem)
}

请注意，根据您的具体情况，您可能需要1.在访问属性时使用self封闭内部; 2.如果写入共享内存，请添加一些锁。

如何加快Swift中循环的性能？

1 个答案: